How to tell the relationship from the shared DNA

Many people have the illusion that if their testing company says a person is a 3rd to 5th cousin they really will be. That is not the case.

The testing companies are just making the best guess they can from the data they have. They do not seem to take segment sizes into account, rather they primarily use total shared DNA measured in centimorgans (cMs) for their relatedness estimates, usually the sum of all matching segments of 5 cM or larger. Close relatives will always share larger chunks with each other and so size does matter here.

Recently I have received numerous questions from people trying to figure out if a new match is a half sibling or a niece or a grandchild. These are hard to tell apart without testing more relatives as they all share about 25% of their DNA with each other. So I decided to collect some detailed statistics on those specific relationships with a google form (click here) that includes total segments and segment sizes for a future blog post [UPDATE as of sept 2017: First round results are written up at ]

The companies predict reasonably well for close family but it is just not possible to be accurate beyond that due to the randomness of DNA inheritance.

For example, here is a picture from the new 23andme of some of the DNA I share with Dick, a 2nd cousin on Dad’s paternal side so blue, and John, a 2nd cousin on Dad’s maternal side so red.


I share a third again as much DNA with John as I do with Dick,  even excluding the 14 cM on the X. The expected amount for a 2nd cousin is 3.125% which is 212.50 cM, right in the middle between these two.
Henry2nds Checking my brother, I see the same effect – he has 282 cM with John versus 185 with Dick. Not surprisingly, when I look at Dad I find that he shares almost twice as much with John as with Dick. Clearly he just inherited more of the same DNA as John’s mother from their common grandparents. Conversely, he inherited less DNA shared with Dick’s mother from his other grandparents.

On the left is a comparison of my first cousin Henry with both Dick and John. The amount he shares with each 2nd cousin is practically identical, as long as you subtract the 40 cM that he shares with John on the X from the total shown by 23andme. Amazing how variable DNA inheritance can be among 2nd cousins.

Click here for the ISOGG wiki article on Autosomal DNA statistics which usually includes the current chart from Blaine Bettinger’s shared centimorgan DNA project.

Personally I have his chart (shown below, click it for a larger version) bookmarked for easy reference. I rely on it heavily.


Warning, DNA testing will show a smaller number of matching cMs and larger number of segments due to their algorithm which removes population specific segments.

The DNA adoption site has a relationship calculator that can help figure out closer relationships discussed in the article at Roberta’s blog called Demystifying Ancestry’s Relationship Predictions Inspires New Relationship Estimator Tool.

Autosomal DNA matching is not cut and dried due to the randomness of DNA inheritance and is even more confusing if you are from an endogamous population because your parents will likely share some DNA due to ancestral cousin marriages. Thus a match could be related on both sides! There is a function on the GEDmatch site that lets you check if the parents of a specific kit are related because they have passed along matching DNA segments.

I have sometimes found that someone predicted to be a 3rd/4th cousin based on total cMs is much more distant. This has happened when there are two good sized matching segments but each segment is from a different ancestral couple. Thus the relationship is much further back, for example, a double 6th cousin.

Another issue is the fact that the testing companies cannot tell which of the two paired chromosomes a match is on. So when you have a match that neither parent has, it is a false match created from small bits from each parent by the computer program (see my IBC article). This is why I prefer to look at matches that are “phased” that is to say a child and a parent have the same match.

If you only match someone on a single good sized segment (greater than 10 cM for most, more than 20 cM for the endogamous) your DNA relative can be anywhere from a 4th to a 14th cousin. See for a further discussion of that.

UPDATE 10/17/2017: There is now an easy to use online calculator based on Blaine Bettinger’s lastest chart at: that will show you all the possibilities for the shared cMs. Then you can use the ages of the testers plus test more relatives to try to figure it out.

Last but not least here is my data collection form which you can fill out right from this blog post (use the slider on the right to scroll down it to answer all questions).


321 thoughts on “How to tell the relationship from the shared DNA

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  1. Thank you for this! 🙂 Especially with the half-sibling vs. grandparent to grandchild or aunt/uncle to nephew/niece relationship, which are all difficult to tell.

    • Kalani,,,, I am also looking into info on DNA test I did on ancestry.. I do see half sister at 1453cm @ 55 segments.. But we also both match possible grandmother with 1008 CM @ 45 segments showing as1st cousin. How can we know for sure ,our father was adopted at birth so we have no records

    • My daughter just found out she shares 314 centimorgans with the son of someone who claims to her half brother.

      Is that possible?

      I have sent my sample in but no results yet.
      Doesn’t her 314 cms already rule out a nephew connection which also would negate a half brother connection?

        • Thank you so much for your sincere and eloquent explanation.

          I am so illiterate about all this centimorgan stuff and have always accepted my teenage ignorance in getting a girl pregnant and later my kids with my wife of 48 years now had a half brother.

          However my daughters 23andMe results shows the half brothers child matching my daughter with 314 centimorgans.

          Because of my lack of knowledge and expertise that you have are you explaining to me that the so called nephew with 314 centimorgans with my daughter cannot be her nephew and my grandson?

          My results has not come back yet but if my daughter is 314 with the boy is there a way to make an educated guess what my centimorgans with the boy would be?

          Am I wrong in assuming that if my daughter can’t be his Aunt that my centimorgans will show I am not his grandfather?

          Forgive my confusion… I just want to be able to understand your profound words.

          Thank you for you time and effort in responding the first time.

          Shocked and confused,

      • Let me first say I’m sorry. I’m sure I’m just overlooking or overthinking something somewhere! Lol. I dad ancestry dna. Came up with someone I don’t know with 1339 cm across 29 segments, longest segment was 190. What is that? Half nice? Half sibling? I don’t know who my father is but I think this is going to point me in the direction need! Thanks in advance!

        • I think that 12% is just right.
          With your parent you share 50%
          With your half-sibling you share 25%
          With your half-niece you share 12,5%

    • I am in shock… my jaw is on the floor… I am in disbelief.
      Seriously I am indebted to you for taking the scales off of my eyes.
      My daughters 341 centimorgans with the story that has been pushed down our throats and me blindly accepting it.

      Am I dreaming?

      So you are telling me when my other daughter and I receive our 23andMe results back my other daughters centimorgans will be similar to my daughters readings that has already been tested?

      Seriously my numbers will not be able to reach the grandfather level? I just can’t grasp it because I am numb. You in a few words have done something amazing.

      Let me just ask one more time and I apologize… because my daughter is at 341 my centimorgans will not reach the grandfather level. This is what you are expressing to my ears, heart and eyes?

      Yes I will recommend you to everyone.

        • Ancestry told my brother that he shares 3425 cMs with a Mary, indicating parent/child. But, is there any possibility that my other brother is the father, without knowing his cMs? Or not possible? Thanks Kitty . Vicki

    • Got my 23andMe test back and I share 999 centimorgans with the boy who is supposed to be my grandchild.
      The test tells me he is my great nephew.

      My brother and sister tell me the test results is not enough proof.

      I want my supposed son to take the test.
      Until then my siblings believe the 999 centimorgans child is my grandson.

      Tell me I can trust the test 100%
      Tell me the boys father and my supposed son is going to be my nephew.

      My siblings have turned on me wanting to believe a lie over the 23andMe results of 999 centimorgans.

  2. In my project using 23andme comparisons there is a difference in segment counts for one relationship vs another.

    Grandparent-grandchild from 23 segments to 37 segments. The 37 segments is an outlier with 3 X-chromosome segments. Grandmothers appear to share a couple of more

    Ethan vs. Robert, 21.9%, 1629 cM, 23 seg (zero X-chromosome)
    Ethan vs. Janice, 25.4%, 1892 cM, 26 seg (zero X-chromosome)
    Ethan vs. Rocky, 22.0%, 1638 cM, 24 seg (79cM X-chromosome, 2 seg)
    Ethan vs. Vivian, 28.0%, 2082 cM, 37 seg (103cM X-chromosome, 3 seg)

    Kalea vs. Robert, 24.1%, 1792 cM, 25 seg (zero X-chromosome)
    Kalea vs. Janice, 25.7%, 1909 cM, 26 seg (full X-chromosome, 182cM)
    Kalea vs. Rocky, 28.1%, 2089 cM, 23 seg (full X-chromosome, 182cM)
    Kalea vs. Vivian, 21.9%, 1631 cM, 25 seg (zero X-chromosome)

    Shay vs. Robert, 21.8%, 1625 cM, 23 seg (zero X-chromosome)
    Shay vs. Janice, 28%, 2085 cM, 24 seg (full X-chromosome, 182cM)
    Shay vs. Rich, 19.7%, 1466 cM, 24 seg (full X-chromosome, 182cM)
    Shay vs. Marcy, 30.1%, 2236 cM, 29 seg (zero X-chromosome)

    1/2 sister vs. paternal 1/2 brother, 26.6%, 1978 cM, 32 seg (share no X)
    1/2 sister vs. paternal 1/2 sister, 29.2%, 2176 cM, 35 seg (share full X, 182cM, 2.45%)
    1/2 sister vs. paternal 1/2 sister, 23.0%, 1713 cM, 31 seg (share full X, 182cM, 2.45%)

    Paternal aunt vs. paternal nephew, 26.7%, 1984 cM, 46 seg
    Paternal aunt vs. paternal nephew, 26.2%, 1946 cM, 46 seg
    Paternal aunt vs. paternal nephew, 24.9%, 1850 cM, 42 seg
    Paternal uncle vs. paternal nephew, 21.7%, 1611 cM, 46 seg
    Paternal uncle vs. paternal niece, 25.0%, 1857 cM, 55 seg (includes 2X seg, 81.6cM)
    Paternal uncle vs. paternal niece, 24.5%, 1823 cM, 53 seg (includes 2X seg, 81.6cM)
    Maternal nephew vs me 20.1%, 1495.4 cM, 35 seg (includes 1X seg, 18.5cM)
    Maternal nephew vs my full sister 28.6%, 2127.8 cM, 40 seg (includes some completely identical X seg, 169cM)

    • I miss stated (completely identical X-segment), I was thinking about his mother and my sister sharing a large amount of completely identical X chromosome.

    • Kitty… I appreciate your help deeply and you sharing your vast knowledge and wisdom on this subject with me.
      Let me also apologize if my words seemed bitter.
      It certainly isn’t bitter toward those who had no part in being born.

      The bitterness you picked up on is from this sudden frustration all of this has caused with my sister and brother.

      When my first daughter had the boy pop up on her 23andMe results with 314 centimorgans linking him to my daughter as a possible first cousin once removed or second cousin my sister claimed the numbers couldn’t be right and of course my brother claimed we were pointing a finger at him and denied any possibility he was with the boys grandmother 46 years ago.

      Then when my second daughter who also took the
      23andMe test came out with 321 centimorgans proving my first daughters results were not some possible “outlier” (as my sister claimed) number and again my daughter was told by 23andMe that the boy is a possible cousin type relationship but not a half-nephew.
      My sister then said you can’t trust the commercial testing companies like 23andMe. My sister claims they are sloppy with their relationship charts.
      My brother also again denied being a part of this after my two daughters have had centimorgans in the low 300s with the boy who was supposed to be their half-nephew.

      Then my results finally came in at 999 centimorgans with the boy and I was told I was probably a great uncle and my chances of being a grandparent was at zero.
      I shared these facts with my sister and brother and they again rejected the numbers saying it is just sloppy testing ect.

      They also accused me of trying to convict my brother as the culpruit, which I haven’t, I have only stated 23andMe is showing the boy as my daughters second cousin and I am showing up as a great Uncle which is conflicting with the story that has been told to us for 46 years.

      I have asked my daughters “half-brother” to participate on 23andMe and now his mother is calling and messaging my family with ugly words and again making up stories and claiming she was never with my brother.
      So yes… you probably picked up some bitterness and I apologize but my own siblings attitudes and how I have handled it has created some bitterness.

      I am only looking for the truth. I can’t understand how my daughters have a second cousin that is supposed to be my grandson.

      My surprise is my brother hasn’t volunteered to participate in the 23andMe testing. If that was me it would have been my first response but after all these years and all the ugliness that has been heaped upon me by my very religious family members I have nothing to lose.

      Sorry for going on and on. I will understand if you have no more advice.

      I do question how it is possible for the centimorgans of 999 with the boy (great nephew) can jump up far enough to make his father my daughter’s half-brother or my son.
      Because of my ignorance of the process and how these numbers work I didn’t know if it was a mathematical impossibility for that to happen. Can my daughters half-brothers biological son who shares 999 centimorgans with me magically jump up high enough when his father takes the test to make him my son? I am so confused!

      Thanks again,

      • I feel your pain Rob. I am sorry you are being treated like a bad guy here. I agree that your brother ought to test but people cling to their ideas…

        Your presumed son’s DNA will show 100% if he really is your son because he gets half his DNA from you (but see below). He could just have passed along more of his mother’s DNA than yours to his son whose match with you will not change. My niece only has 17% from my Dad rather than the expected 25%, still a little bit more than your 999. That number is extremely unlikely for a grandson but not impossible.

        There is a possibility that the sperm you made the son with were actualy those of a twin brother you absorbed in the womb. That is called chimerism, extemely rare. But then your own sperm created your daughter. Seems rather unlikely but it is possible see

        • Thanks so much for your kind words and directions.
          This is all so new to me from centimorgans to chimerism.
          I also realize you are very busy as a professional and my questions and situation must seem so elementary.

          Perhaps I just misunderstood starting with by biological daughters who only share 314 and 315 centimorgans with their supposed half-nephew.
          My daughters got their results back before mine.
          I was just assuming that because I figured this as a puzzle and if their centimorgans didn’t fit as being his half-aunt it scientifically took me out of line but was willing to send my DNA in.
          Then when my 999 centimorgans came back again I just assumed it had to fit as a puzzle. In other words if my daughters weren’t half aunts but 1cousins once removed that is how I would put the next piece of the puzzle in when 23andMe stated I was a great uncle and when I put the number 999 in the DNA Painter it read 100% Great Uncle and that the grandparent relationship has a zero probability.

          I do think I have convinced my “son” to send his DNA in because his son is showing up as my great nephew and my daughters first cousin once removed. It would motivate me to test but we are still waiting from them to respond.
          I have no idea what my brother is doing other than denying it all.

          My two questions to you as an expert would be is it even possible for my daughters 314/325 centimorgans with this young man jump past 1160 to make his father their half-sibling?

          Also since I only share 13.39% (999cM) with my supposed grandchild is there even a possibility my DNA can even go up to the 44.91% (3350cM) it would take to make his father my son?
          From your perspective as an expert is that kind of increase in centimorgans in those two cases even possible?

          Thanks again you have been so kind in sharing your knowledge,
          Rob… lost in the land of centimorgans!

          • Of course, your daughter’s sharing only 323 and 319 make it clear that they are almost surely 1C1R. Perhaps I skimmed

            I presume you share the expected amount with your daughters.

          • Yes we have tried to understand it best we could.
            This is all so new to us.
            But all the denial from the other side be it the boys grandmother and mother of the half brother.
            Then my own brother and sister acting as if I am just pulling these numbers out of thin air.
            I was just sharing with all that the low centimorgans are not in line with what the story that has been told for 46 years.
            That is why I wondered if it is even possible for centimorgan numbers to jump high enough in each case to the half-sibling and father range. The grandmother and my brother are so adament that we are even bringing this up. They are telling us the proof is “my” DNA is in the boy and that is all the proof they need. That is what I am dealing with.
            Again that was why I questioned if 999 centimorgans could jump in the father to 3350 level.

          • Yes… my numbers with my daughters were at 3700cMs each which is at 50% as you already know.
            This is why I can’t see how my daughters cMs of 314/325 (13.4) with their 1cousin1R can jump to 25% with what is supposed to be their half-brother? We are hoping he partakes in the testing.
            It seems to me if the son of the supposed half-brother is in the low 300s won’t his father when he tests turn out to be a first cousin with my daughters and then my nephew? How can it be possible to jump over the nephew catagory to be my son? Am I reading this wrong because of my lack of understanding? Is that possible for 999 cMs with a great nephew turn magically into the 3300s to make his father my son? Doesn’t all these centimorgans each of us share have to follow a pattern in the relationship chart? If my daughters are 1cousins1R doesn’t the puzzle make the boy with 999cMs with me a great nephew? In other words my daughters can’t be cousins to the boy and then me be the grandfather? Sorry for me being such a dunce about all this.

          • Rob –
            I get that you have been badly treated by your family over this and I am sorry about that. Sadly many people do not trust science these days …
            Yes the matches with your daughters indicate that the only way that you are the father and grandfather would be chimerism which is very unusual but not impossible although odd since your daughters are yours.
            It would be best if your brother tested too.
            You can also ask your doctor if your sperm can be tested for chimerism but it would have to be a mix because of your daughter. See

          • Kitty once again thank you for you kind input and the sharing of your expertise.

            We have sent in one of my grandkids DNA to be tested.

            Also the illegitimate son said he would participate.

            My brother said he would test too but as I look back all of the DNA evidence is simply stating the truth.

            They will have to accept that the grandson is actually my great nephew and his father is my nephew.

            My brothers denial and reluctance to test makes me think he may be hiding something he won’t admit.

            If the test shows the man is not my son but my nephew then we will see what my brothers test show.

            I will stop bothering you until I have their information.

            Thanks again for all your help,

          • Kitty once again thank you for you kind input and the sharing of your expertise.

            We have sent in one of my grandkids DNA to be tested.

            Also the illegitimate son said he would participate.

            My brother said he would test too but as I look back all of the DNA evidence is simply stating the truth.

            They will have to accept that the grandson is actually my great nephew and his father is my nephew.

            My brothers denial and reluctance to test makes me think he may be hiding something he won’t admit.

            If the test shows the man is not my son but my nephew then we will see what my brothers test show.

            I will stop bothering you until I have their information.

        • Greetings Kitty,
          Just an update.
          If you remember I had a question about a possible grandson/Great Nephew I shared 999 cMs with.
          The DNA calculator told me I had zero chance of this being my grandson and it predicted great nephew.

          I convinced the boys father to take the 23andMe test. His results could be here any day.

          My question is this… Is it even possible for my centimorgans with his son at 999 (13%) to jump all the way to 3700cMs making his father my son? Is that even possible? I am so ignorant about all this.
          Thanks Rob

          • Rob, the parent child relationship is unmistakable in the DNA so you possible son’s results will answer your questions. No your possible grandson’s match with you will not change. The possibility is that his father gave him lots more DNA from his mother’s side rather than from you. This can happen in the random reshuffling of DNA

          • Got my granddaughters test back today.
            She shares 72cMs (0,96 %) with my great nephew according to 23andMe.

            My granddaughter shared 22.5% with me.

            My brother is offended that we don’t believe him that he is not involved.

            We are still waiting on the one test that will end all the speculation.

            If my granddaughters numbers are this low could she still be a half-cousin with 72 cMs 0.96%%?

            They are putting me through hell for just asking my brother and the alleged son to participate.

  3. Hi I saw your question posed on Facebook but wasn’t sure how to complete form properly so I’m happy to give you GedMatch numbers so you can take a look if you like

    Grandson (M4+1) A347430 and his Maternal Grandmother (M0) A903999
    Note Grandson’s paternal great grandmother is Ashkenazi/endogamic. Grandson is 8% European Jewish according to Ancestry.

    Nephew (M4+1) A347430 and his Aunt (M2) A219400
    Nephew’s paternal great grandmother is Aunt’s paternal grandmother. She was Jewish.

  4. Sorry I’m of no help, but I share 811 with a great uncle and 942 with a great aunt. When my mother gets her results in a few weeks, we will know how much is shared between her and her aunt.

    I did have a quick question. On 23andme, my great uncle got a little (0.1%) Sub-Saharan African. I was wondering if all the ancestors he has, I also have, but he doesn’t have all the ancestors that I have? And if he has African ancestry from a slave (as he has deep ancestry is from Kentucky and Virginia), would I also have that ancestor, just no Sub-Saharan African showed up for me on ancestry?

  5. The maternal or paternal question has now been added to the bottom of the form
    Please any of you who still have the window open so can edit their response, add that information. Anyone who cannot edi,t send me the answer with the total cM and aprox time and date when you added your numbers, thanks!

  6. Done – this was an interesting exercise. I provided information for me and my two brothers compared with my mother’s sister and my mother with my mother’s sister’s daughter.

    I also added my half brother, but that is from (he hasn’t gotten around to doing more with his DNA – hopefully soon I’ll get him on GEDmatch).

  7. This is very timely as I am trying to figure out if my FIL has found an aunt or a half-sibling to his match. They match at 2009 cM with 45 matching segments, the largest being 199.3 cM’s. FIL was b. 1947 and the match was b. 1938, so this is probably not grandparent/grandchild relationship.

    We did not know of this family, I was looking for a different paternal family.

    The match has a nephew (a son of her sister) who matches at 1548 cM and 42 matching segments with the largest being 100 cM. The nephew was b. 1973. It is assumed that the nephew and the aunt are full matches, not half, but the nephews mom has not yet tested.

    The nephew matches my FIL with 747 cM’s and 26 matching segments, the largest being 77 cM’s.

    I am going to fill out the Google document for each. Thank you.

  8. Dear Kitty,
    Thank you for this helpful blog post. I recently uploaded my DNA to Gedmatch from Ancestry. I am adopted and know my birthmother. My half-sister will have her DNA results soon. However,I had an interesting match come up and using your Google form, it appears that the gentleman in question is either a half-sibling, Uncle, or Grandparent. I was surpised given that our shared cM’s are not that high- 59.8. Perhaps I filled out the form incorrectly. Thank you in advance for any thoughts on this matter.

  9. Hi Kitty. I have entered two grandparent/grandchild and six aunt/uncle to nephew/neice for you! Will be interested to see the outcome of this data analysis.

    • Ms.Kitty,
      I did DNA testing through AncestryDNA. I have a match with 1286 cm across 27 segments with the longest segment being 144 cm. I am 49 years old and the match is only 16. Her mother and I have been trying to figure this out because we do not know each other. I’ve looked at DNA painter calculator and other resources. Because of our ages, I believe she has to be my half niece. I don’t see any other possibility that makes sense based on our age difference. Is this what you believe our relationship is too or is there another logical explanation?

      • Half niece is very likely. You and her mother should look at the shared matches and see if they shed light on the relationship.

        Presuming her father is likely your half sibling, are his parents known? Does your genealogy line up with your DNA matches? Does his ( or his daughter’s)?

        If you both tested at Ancestry see this post for using your matches to confirm your family tree

        • Kitty,
          I did not know until I saw the results this morning but the girl’s father tested with ancestry. He popped up as a close match this morning. 2055 cm across 31 segments with the longest segment being 182. It says 29% shared DNA. He is 51 and I am 49. Does this mean he is definitely my half-brother?
          Thank you so much for replying. Neither of us knew our parentage was in question until his daughter showed up as a match to me. I looked through all shared matches to her yesterday and see relatives on both my paternal grandmother and grandfather’s side. I assume this means my father is his father which will be a shock to all I’m afraid.

          • Yes he is your half brother sharing your dad. Sorry this is a shock. Does he have siblings? Was he born long after his parents married? It could have been a sperm donor situation. I know of cases where a man was infertile and recruited a friend to donate sperm.

          • He is the oldest with two younger brothers. I am the oldest as well. All of the “parents” would’ve been in their late teens and unmarried. My father would’ve been in his first year of junior college. I honestly do not believe my father knows. This all would’ve happened about a year before he met and married my mother (thank goodness). My parents are celebrating their 50th anniversary next Saturday. They didn’t date but a few months before marriage. Both of my parents were aware I did AncestryDNA testing several years ago and weren’t concerned or against it at all. I did it for fun to see my ethnicity estimates.
            I haven’t spoken (messaged) to this man, only to his ex-wife. I did know she told him about it and they didn’t believe their parentage to be in
            question. From her messages I can tell they were both thinking I was his late father’s daughter. I have not shared with them that I have researched our shared matches and recognize names from both of my grandparent’s families.
            I honestly do not know how I would even go about telling my parents this or how they’d react….(I’m concerned it would not be a good reaction) I’ve told my sister and she is very against my telling our parents or her having any relationship with him. Besides my husband, she is the only person I have told.
            I haven’t reached out to this man yet or spoken with his ex-wife in a couple months. If he just got this news yesterday I can only imagine the devastation he may be feeling if he has realized his father wasn’t his biological father. I think maybe it’s better if I wait for a message from him and give him time to process things.

          • Beth,
            It is never good to be the secret keeper. Since it was before your parents met, it should be fine to tell them about it. Perhaps even ask your dad to do a DNA test.
            As to your half brother. Up to you how to proceed. Waiting on him might be OK but how do you feel about it?

  10. I completed the form for my match with someone who we both grew up believing we were 1st cousins. Recent revelations have caused us to wonder if we might be half-siblings. Thank you for helping us.

  11. I took a DNA test in Ancestry . 1 girls on 50, one 52, and I’m 58 matched my DNA . They have 1600 and 1700 centrimorgans of mine. They were both adopted at birth. The one with 1700 centrimorgans said she found her birth mother before she died. She ask her who her father was and she said Dennis Williams, That’s was my dad. I knew then she must be my 1/2 sister. The other girl shares 1600 centrimorgans she was adopted at birth in Oklahoma City. We lived there too.
    They have 47 segments .
    How can I be sure they are my 1/2 sisters? I believe they are I can’t be their grandma, aunt , cousin etc,

    Cindy K

    • Enjoy knowing your new half sisters. I am sorry if this is distressing to you but DNA does not lie and those numbers are very clear.

      To be sure they are your half sisters, have everyone upload to GEDmatch and compare your X chromosome. Women with the same Dad will always share a full X (occasionally if different companies or different chips there can be a small break in the middle). See

      • Hello mskitty – I am female. 23andme identified a paternal “half sister” match (different mother’s, potential same father) at 17.7%, sharing 1315cM, across 28 segments, 181.84cM on the X. There apprx 8 segments where we share 70 up to 100+ cM’s. It is such a borderline total cM number. She was adopted and she spoke with her birth mother only once (due to rejection/secretive nature). With such borderline numbers I keep flipping back and forth if she really is a half sister. I think she will be open to doing GEDmatch (I’m meeting her for the first time next week Feb 2019). Anyway, looking for your insight as to what you think.

        • When did you each test? Are you tested on the same chip? Normally sisters sharing a Dad will share a full X but there are small inaccuracies with different tests.
          How large are the 4 largest segments? read this post, it would seem to confirm half sisters

          Yes both upload to GEDmatch, MyHeritage, and family tree DNA for more matches and test at Ancestry which has the largest database

          • Thanks for your reply. I had my testing done ~2016, my half sister just did hers this past year (~Feb 2018). I’ve been reading extensively about X and did find the following “There is almost always a bit of recombination on both far ends of the X chromosome – even from father to daugher. Changes in these SNPs can be ignored. The total X chormosome is 196 in length, but full matches may be slightly less then this.”. For us 14 cM is missing on our X comparison on the far end only. Strong overlaps are: X-182cM, 1-62cM, 2-105cM, 3-73cM, 5-101cM, 6-91cM, 7-70cM, 8-90cM, 11-110cM, 12-75cM, 20-41cM. Total-1315cM, 28 segments. We have 151 shared relatives on 23andme, unfortunately none are closer then 2nd cousins; other then one oddity where a person is listed as a 1st cousin to her and a 2nd to me where the percentage is truly double. I have sent him a message to learn more about him. The large majority of all other matches are very closely percentage-wise to both of us, other then 2 or 3 which say 2nd cousin for me and 3rd for her, and visa-versa. Another bit of information I just received from her is that her maternal half brother appeared recently on 23andme. She matched him at 28% (why so much more then me??). She has spoken to him and indicated that their mother’s sister is still alive, and he will be contacting her to see if she knew who the father was. I think it’s great that 23andme has found this match for me (we are not shocked, displeased, or the like), I’d just like to solve the mystery. Since my father had 2 or 3 of his brothers (now deceased) in the metro area when she was conceived, I’m trying to figure out if perhaps they, my uncles, could be her father. I’ve contacted 2 of my sisters so far with the news and they too will be doing 23andme to start with. I do have a brother and have yet to contact him with this information. Would he perhaps have a stronger match to this potential half sister? I have recently obtain the Ancestry test kit and will be submitting it. I will encourage her to to the same, along with GEDmatch, etc.. Thanks for the link and any further input from you is greatly appreciated. Sorry for the long post. Have a great day!

          • yes it is quite likely that the different test dates mean the chips tested slightly different SNPs on the X. Most testing companies do not test the very ends of the X where there is a little recombination with the Y so I usually do not mention it as it just confuses people.
            With autosomal segments that large she is surely your paternal half sister. Congrats!

          • From a few more relatives appearing on 23andme, it turns out that my 17.7% match/182cM on the X and the classification that I was a half sibling has now been disproved. I am a (half) cousin to this women.

  12. Pingback: Relationship Estimates - Beneath the Cairn

  13. Hi Kitty,

    I’d done the Ancestry DNA as has my first cousin (maternal) and his father (my maternal uncle), but the “relationship” came up not as expected. My cousin matched with me at the level of 2nd cousin (293 centimorgans shared across 14 DNA segments) and my uncle matched at the level of 1st cousin (797 centimorgans shared across 35 DNA segments) which was my first hint that something was a bit off (on the other hand, a first cousin on my paternal line matched exactly as expected). So…I had my mom do the test. And she matched to her brother at the level of first cousin (1,761 centimorgans shared across 60 DNA segments). From my reading here, my assumption is that they are more likely to be half-siblings than full siblings (they are about 10 years apart). I’ve also read about looking for large segments of green on GEDmatch one to one compare and am hoping they will upload to GEDmatch so I can do so.

    My assumption is that they have different fathers vs. mothers as having different mom’s would mean my grandmother raised another woman’s child as her own…which I feel would be highly unlikely. But want to make sure I rule in and out every possibility before I present this info to my mom and uncle. My question is how I would be able to tell if they had different mothers vs. different fathers?

    • You are right that they almost surely have different fathers. If they both upload to, you could check their X, if they share a significant chunk or two then they have the same mother. However if they share no X, it is not a sure thing that they have different mothers, just about 98% or so (a guesstimate).
      Best is to compare each of them to their maternal and paternal side cousins to confirm which lines they match on. 2nd and even 3rd cousins will do for that.

  14. I have done the Ancestry DNA autosomal test a couple of years ago. I have noticed a trend of DNA shared with me of some of my cousins on strictly the paternal side and have compared the results with the DNA Detectives chart. The results have been for the most part, trending lower than the average cM shared as per the chart, going from my closest to the more distant known cousins..
    Examples: One cousin shares 975 cM across 42 segments which meets the charts average cM shared expectations – no argument there: A first cousin once removed shares 270 cM across 15 segments with me which is very low, compared to the average per the chart of 450 cM; a 2nd cousin shares 215 cM with me, which is below the average of 224 cM; A 3rd cousin shares only 14.1 cM across 2 segments and says I’m a 5th to 8th (distant) cousin which is absolutely not true and the average is supposed to be 56 cM; I also have a 3rd cousin once removed, who only shares 13.6 cM across 1 segment and says I’m a 5th to 8th cousin (distant) which is very low because 30 cM shared is supposed to be the average per the chart.
    It just seems like my paternal grandparents all the way back to my great-great grandparents (paternal) did not share much DNA down to me or my proven known cousins. Why??
    With this below average trend of shared DNA, is it possible that my 5th cousin and her Aunt would only share 4 to 5 cM with me, if I uploaded my DNA to Gedmatch? I would expect so. I did notice an online chart, similar to the DNA Detectives chart on that also.

    • Tony,
      DNA inheritance can be quite random after close family. I only got 22% from my maternal grandmother, rather than the expected 25%. As I discussed in the article one 2nd cousin shares twice as much with me as another but this did not hold true for my first cousins with those same 2nd cousins.
      After 3rd cousins it gets more and more random, so don’t read anything into it.
      However, do check of you have matches on all lines since another explanation for consistently sharing less is that they are all half cousins and there is an NPE up your paternal line.
      Finally, do be aware that ancestry removes pile up segments so their numbers can be lower.

  15. Is there any way to determine that this information from ancestry can definitely determine whither a person is a niece or a first or second cousin. From ancestry this person shares 418 cm across 22 segments. We know that she is my nephews child. When my grandmother was 41 and her oldest child(my mother ) was 13 she past of complications of uterine hemorrhage and my mother and her siblings we spit up in different states. My mother and my “sister” was the only ones kept together. Strangely my sister”s birthday is only days after her the date on her signed death certificate. We were wondering if my mom and sister are really siblings instead of mother and daughter. If they were said to be mother and daughter to keep them together. My grandfather ended up in prison about that time. My mother and her siblings are all dead. My sister was 27 years older that I am. My sister is my nephews mom.

    • Carolyn –
      This is a bit complicated of a story. Can you test your mother and your “sister”? If so, you uploading their results to GEDmatch then comparing them would tell us. But it sounds like you are trying to determine this from other tests?
      Your great-niece shares less than the normal amount of DNA for that relationship. But ancestry removes some matching segments so again, get those numbers fromGEDmatch. See this page for expected amount of shared DNA for different relationships

  16. Me and my first cousin share 6.4 .But 23 and me says we are first cousins once removed.I beleave my grand father is my real father.And his mother is my half sister.I think thats why 6.4 not 12.Please help with all combinations.

    • Allen –
      I gather you mean percent? we usuall talk centimorgans (cMs) in genetic genealogy. You would share more DNA with your “cousin” if your father was his grandfather not less as you do. The amount you share suggests that you might be half first cousins (your related parents being only half siblings)

      See the chart here

      I would recommend you test more cousins related via this family and make a mcGuire chart to see if you can figure out the relationship

      • My sister took a DNA test and shows 31.% matches.But our heritage is different.I have Native American, Jewish, and she does not have them plus her % of others are very different.She has German I don’t.Could we be half-siblings or full?We do share English just about 30% difference between us.

        • Allen –
          Ancetry composition determination is far from accurate yet but shared DNA is very accurate.
          However it sounds like you might be half siblings since you are so far from 50% shared (total cM = ?).
          Unless you tested at 23andme, you need to upload to GEDmatch to see if you have a significant amount of fully identical regions of DNA (FIRs). See

          for how to figure that out

          • Thank You! This answers how being the only son and treated so badly.My father never did anything with me like other fathers.He loved my sisters and I never felt that from him.At 15 he told me it was time for me to quit school and get a real job to start paying him back for the years of food and for putting a roof over my head.I got a job and stayed in school given him my paychecks.Now I can understand why he is mean to me.

      • mskitty: Could it be that it could be my uncle could be my father instead of my dad?I’m just trying to understand who I am.My sister took DNA test also ( largest first cousin, I described to you on 8-29-17 as 6.4% and 16 overlapping segments.My sister and my cousin ancestry are very similar.Mine includes Native American, Jewish, a little more of African and I show on the low end of Neanderthals with no German.They show German, and more English than me.

        • Again, you cannot rely on ancestry composition for relationship testing. It is not good enough yet.
          Always look at the actual centimorgans shared. You have the same father as your sister and your cousin had the expected amount shared for a cousin

  17. I’m a newbie, if this is the wrong spot to ask a general dna question, I apologize. I share 1153 cM over 36 segments with someone (Ancestry DNA test).
    How much DNA might we share if this person were the daughter of my half-brother and a woman who is not my mother? Or, the daughter of my half-brother’s son and a woman who is not my mother?
    I feel inadequate at this and I just bought you a glass of wine to thank you for answering such questions.

  18. I am a bit confused. There has always been a question as to my birth father. My father questioned my paternity and my mom denied any problems. I hope that my niece who is a match on ancestry dna at 1347 cM at 52 segments is my full niece . I would appreciate your thoughts as we only share 19% of our dna.

    It also appears that some of my shared matches, match both my father’s mother side with my mom’s side.

    Thank you for your help and wonderful blog.

  19. Hello,
    A group of my family members (father, my 1/2 sister and her 2 kids, my aunt and her daughter) have done 23 & me. I looked at different pairs of relationships -total shared cm’s & # of segments to try and determine if the numbers seemed to make sense based on the closeness of the relationship. I don’t think they do make sense.

    My first question relates to my father and aunt. When I compare their data they share a number of complete cm’s, and a number of 1/2 identical cm’s. Is the total number of cm’s they share the sum of these 2?

    My second question, would my Dad and his grandson share any complete dna?

    My Dad was born 1st and my Aunt followed. I am wondering if my father’s father, is actually the man he believed to be his grandfather.

    Any feedback you could offer would be very much appreciated.

    Thank you

  20. Hi Jane –
    Make yourself a McGuire chart to look at the relationships. I find this most useful for clarifying them

    To question 1: Normally just the half identical segment total is used. However 23andme shows you both totals in the comparison found at 23andme tools > DNA relatives > DNA. Warning, it includes the X and all segments > 5cM so some adjustments are needed to use this with the various charts.

    To question 2: Your Dad and grandson would normally not share any significantly sized fully identical segments unless his Dad is closely related to you.

  21. Thanks again, I will try to do that, but not sure how to find the paternal side.

    Do the number of generations make a difference? Gedmatch says we are separated by 1.7 generations.

    • Gosh, I thought I had a handle on my understanding, but I seem to have confused myself. I do have a cousin match with no x match and we match at 144 cm with the largest at 47 and my niece matches that one with 84.9 with 35.7 at 3.7 generations.

      I think it is from the paternal line, but I have really confused myself. I intend to study this gedmatch info and try to figure it out.

      I can not thank you enough and will continue to follow your blog.

  22. Hi Kitty,

    Here is the info:

    Aunt & Dad
    Half Identical 2858 cM – 44 segments
    Completely Identical 1015 cM – 37 segments

    The possibility I had in mind is
    Aunts Mother = Sally, Aunts Father= Hank
    Dads Mother = Sally, Dads Father = Hanks Father

    Additional relatives who I have 23 & Me data for include:
    Aunts daughter
    My 1/2 sister (share Dad in common)
    My 1/2 sisters daughter & son

    Initially 23 & Me identified my niece as my grand daughter.
    My nephew shares a great deal of both half identical
    And complelty identical DNA with my father (his grandfather)

    Thanks so much for your reply

  23. Hi Kitty,

    Apologies- I didn’t see your reply to my 1st post before adding the 2nd.

    Your answer to my first post took my back to 23 & Me to look at the DNA shared between my father and my 1/2sisters son. the identical DNA shared between them is on X.

    The overall breakdown on their shared DNA is as follows:

    Half Identical 1481 cM – 27 segments
    Identical 53 cM – 2 segments

    When I read your reply about the unlikelihood that they would share any identical DNA I thought that maybe this would be the smoking gun lending possibility to my fathers real father being the man he knew to be his grandfather…. then, I saw the post about x, and uncombined… and I see that maybe it’s not that simple. Any thoughts?

    • A man has only one X otherwise he would be a girl so his X matches are always fully identical, thus that is not meaningful

      As to your puzzle, I am not sure why you think the grandad might be the Dad, those numbers look like normal full siblings to me.

      You could test more cousins related to the grandad

      • Hi Kitty,

        Thanks for the feedback. I created a McGuire Chart plugging in the numbers and was wondering if there is any way I could email it to you? The one hazy area is whether or not the total percent shared for full siblings (via 23 & Me data) is solely the 1/2 identical figure, or, the 1/2 & completely identical added together. I had sent you 2 vinos the other day- hopefully those went thru. 2 more on the way.
        Grateful for your generosity in sharing your knowledge!

  24. Gosh, I thought I had a handle on my understanding, but I seem to have confused myself. I do have a cousin match with no x match and we match at 144 cm with the largest at 47 and my niece matches that one with 84.9 with 35.7 at 3.7 generations.

    I think it is from the paternal line, but I have really confused myself. I intend to study this gedmatch info and try to figure it out.

    I can not thank you enough and will continue to follow your blog.

  25. Ms kitty, have all my questions, I bought you a glass of wine.

    Still trudging forward, but getting cross eyed with numbers.

  26. Hi,

    I have found a cousin on 23andme and our family trees are not connected. My cousin heard rumors that his father’s mother was actually his sister. So Jane and John were raised as siblings, but Jane may have actually been John’s mom. There was no mention of who John’s father could have been. My cousin, James (all names changed), is John’s son.

    Some of my family lived in the same town where Jane was located when she, supposedly, became pregnant with with John. My grandfather and great uncles were near the age of Jane when she got pregnant, 18.

    I ran our 23andme data through the relationship estimator and we are estimated to be 1C1R [11111] or 1C [10110]. My daughter and some cousins on the paternal grandmother side have taken the 23andme test. My mother will be taking the test and another cousin on my paternal grandfather side will take the test too.

    Jame’s DNA Match to me
    Based on Seg of 5 cM or greater
    Total cM 567
    Longest Segment cM 48.2
    # of Segments 21
    % Shared 7.660

    With all the data we have and will have, where can we go to better narrow down the potential relationship possibilities?

    Thank you in advance!

    • One problem with Family Tree DNA is that they include segments smaller than 7cM. After you toss out those smaller segments, if you are still matching for about 500cM then still likely in the first/second cousin range

      Sounds like you are doing the right thing, getting as many family members to test as possible to sort this out. Most important is your mother. Does she have any brothers? If she does not match then it is on your dad’s side.

      Another possibility is for James to get his Y DNA tested which may provide a surname …

  27. I got my results from 23andMe with 1090 cMs, 20 segments, 14.6% shared and says we’re 1st cousins, is that even possible? We are definitely half relatives, if that helps.0

  28. Hi, I could not complete all questions, and I’m not positive of my parents being my actual parents, but my one and only match was with someone I did not know and about 20 yrs younger. Ancestry DNA had put us as 1st cousins at 663 cm & 37 markers? She too is not at all positive of her birth parents. Could she possibly be a half sibling or a half Aunt? Thank you

  29. Thank you so much Kitty! I’m only 2 days new to this and I have read how it works but is so confusing to me, especially having no other DNA with anyone to go by & when I put 35markers, was supposed to be 32. I’m sorry to have had bothered you with this, but I’m just lost…. 🙂
    Thanks so much!

    • Shannon
      Patience … Give yourself some time. Keep reading and looking at your results, it will start to make sense eventually

  30. Hello Miss Kitty,
    More wine coming your way. I’m female and match an unknown man on Ancestry. I’ll call him D.
    •D matches his known half-sister at 1377 (they have the same mother).
    •D matches his own granddaughter at less than 1300.
    •D matches me at 1373 cMs across 44 segments.
    •D’s son matches me at 961 cMs across 25 segments.
    •Ancestry has defined D and me as Close Family –and D’s son and me as 1st Cousin.
    * In the Close Family category, I know D is not a great grandparent or Uncle, nor is he a child of my full sibling.
    * At 1373 cMs, I believe D could possibly be a half-brother or half-nephew.
    * If D is my half-brother, his son is perfect for half-nephew at 961.
    * But if D himself is my half-nephew, then his son’s number is very high for a great half-nephew. What do you think? Thank you so much.

    • Wanda, it sounds like you have answered your own question and eliminated the other possibilities. He is your half brother. It would be good to get him to upload to GEDmatch and I would happily look at the comparison there for the two of you.

  31. Hi Kitty can I call upon your expertise.
    I have a match on ancestory as a 1st cousin, we share 804cms (gedmatch)
    i share 373 cms with his daughter
    he was adopted and only info was that his bio father was a young (my name)
    I have no idea who my fathers father was as he was brought up by his grandmother (young)
    at 1st the result looked as though I am a half Nephew but there is a 3rd person who he has a match with as do I on ancestory who is a relation of my grandmother (young nee bushnel) he comes up as 3rd or 4th cousin
    he hasnt uploaded to gedmatch

    any thoughts?

  32. Kevin –
    That is really not enough information. What are your relative ages? So the issue is that if he is a Young why does he have this 3rd/4th cousin match with your grandmother? Sounds like he is related to your Dad who would have both lines. Did your Dad or you have any brothers?
    Get as many known relatives of yours to test as are willing to help with this mystery.

  33. Sorry Kitty I didnt put it very well.
    I am 62 he is 70
    the 3rd/4th cousin is the relation to me to the 3rd person who is a descendant of my great grandparents.
    my dad has a couple of living cousins as do I so i will see if they can get tested


  34. Basically want to tell what relation he is to me
    this is the gedmatch result

    Chr Start Location End Location Centimorgans (cM) SNPs
    1 238,254,256 240,773,066 7.6 716
    2 77,916,406 133,326,827 42.8 5,861
    2 202,658,096 235,840,151 48.0 5,526
    2 236,089,121 242,565,979 13.4 1,207
    3 120,836,583 151,154,829 32.1 4,311
    3 157,730,821 187,609,004 30.2 3,766
    4 6,829,453 10,337,857 9.8 824
    4 84,460,381 92,046,301 8.4 1,025
    6 6,171,146 21,798,151 27.8 3,191
    6 124,399,036 138,863,401 18.4 2,268
    7 7,972,287 26,162,119 27.7 4,051
    7 145,948,007 152,927,182 15.4 1,356
    8 37,288,402 72,408,012 27.0 3,726
    8 74,856,303 115,097,126 29.3 4,700
    8 139,853,147 146,241,933 10.7 1,143
    11 22,308,958 108,678,237 71.1 11,209
    12 93,073,105 126,075,474 47.1 5,852
    14 52,679,619 99,760,931 64.1 8,221
    15 20,614,243 37,027,402 37.9 3,141
    15 67,910,978 77,127,099 8.4 1,168
    15 93,491,713 98,574,626 14.8 1,241
    16 7,400,811 10,252,326 7.4 849
    16 12,199,639 22,744,262 16.8 1,577
    17 10,164,422 58,988,240 63.1 6,979
    18 102,535 2,881,478 8.4 662
    19 489,994 38,923,549 56.7 4,535
    19 40,112,681 57,932,919 32.2 2,941
    20 7,448,401 13,190,328 13.4 1,290
    22 37,959,275 43,840,446 8.6 1,007
    Largest segment = 71.1 cM
    Total of segments > 7 cM = 798.7 cM
    29 matching segments
    Estimated number of generations to MRCA = 2.1

    435222 SNPs used for this comparison.

    • The data is a very good fit for half uncle. There are other possibilities based on cMs and ages (1st cousin, half first cousin) but the low number of segments suggests a close relationship.
      How large is the match to your grandmother’s line by this 3rd person? Unless his match to you and to the adoptee triangulates these could be from different unrelated lines. For example this 3rd person could be related to your grandmother on one line and to the adoptee on a totally different line.
      Get a few more cousins to test, a cousin on each grandparent’s line and perhaps each great grandparent line also … the more the better!

      Also if you are interested in figuring out who your father’s father was, go to and take some classes or just read their materials.

  35. Fantastic post Kitty. Thank you. I have my own situation I was hoping to run past you:

    I have a match on AncestryDNA that is 793 centimorgans shared across 32 DNA segments. Ancestry thinks that this is my first cousin.

    I can identify this person as being from my mother’s father’s side due to ethnicity. My mother was adopted and she never knew her birth parents. It is almost certain that her birth parents never had another child after her.

    Accordingly, I am almost certain that this person cannot be my first cousin.

    I believe this person is my mother’s half-sibling, i.e. my half-uncle. Do you think this is correct? The only other relationship I think could be possible would be first cousin once removed (i.e. my mother’s father’s sibling’s child, i.e. my mother’s cousin). However I looked at the histograms for the latest SharedCM project (August 2017) and this would put us in the 99th percentile for amount of DNA shared, which seems very unlikely.

    Can you tell me if my analysis is correct or if I’m missing anything? I am also a little vague as to the significance of / context for our centimorgans being shared across 32 segments.

    I would be so grateful for any light you can shed on this!

  36. A mother, her brother, her son, her daughter compared to a non-related Male and his Half brother.
    Only the Daughter’s Autosomal test matches the non-related Male. 48.5cm Total and 48.5 largest.
    Is the Daughter alone, apparently related to the otherwise non-related Male from her Mother’s side?
    The individuals do not share matching mtDNA haplogrouping.

    • The daughter would be related to the unrelated male on her father’s side since her mother does not have this match. I removed the kit numbers, we never publish these for privacy but I will take a quick look and email you.

  37. I uploaded my raw DNA to GED MATCH. Not sure why because i have no idea what all this means. are there people you can hire to look at these results . says i have 90 matches. i have like 3 that are highlighted in green. Ughhhhhh ,
    any help would be appreciated.

  38. I have a question about full vs. half siblings. I am an adoptee that has found my bio mom and siblings. My brother and mom both tested at Ancestry and I uploaded both to Gedmatch. My son tested at 23andme and I uploaded to Gedmatch.
    As far as I can tell my brother and I are full siblings. Our mom is from the San Luis Valley. The gedmatch test for “are your parents related read”:

    Mother 4.6
    Brother 2.5
    Sister(me) 2.8
    My son parents not related.

    Our numbers on Ancestry are:
    Brother to sister 2,515 65 seg
    Brother to mom 3,478 49 seg
    Sister to mom 3,458 62 seg

    Our numbers on Gedmatch are:
    Brother to sister 2635.5 145.9 on X. Gen 1.2
    Brother to mom 3586.2. 196.1 on X. Gen 1.0
    Sister to mom 3586.1. 196.1 on X. Gen 1.0
    My son to brother 1815.6 145.9 on X. Gen 1.5
    My son to My mom 2158.8. 174.1 on X. Gen 1.4

  39. Suzanne-
    All those numbers look pretty normal but I am not understanding the “are your parents related?” result – are those generations (gen) or cMs? Does your mother know who your father is? And who her parents are? I will email you

    • Hi Kitty,

      The “are your parents related” result on Gedmatch is given in MRCA form: most recent common ancestor. My mother is 91 and has dementia so I don’t know if she would be able to tell me.

      Thankyou for any guidance you can provide.


  40. My closest match is the data below. Can someone tell me if this person would be related and if so approximately the degree of relation? Thank you.
    Total CM: 26.6
    Largest CM: 10.1

  41. Literally at my wits end trying to help family only to realize I’m the one who needs help in order to provide them help…if that makes any sense?
    My cousin, lets call him “A”, contacted me out of the blue because I’m the “family tree guy” in the family. He told me he’d done the AncestryDNA test & the 23/me DNA test and that he was contacted by a woman on 23/me, let’s call her “B”, she’s about 69 years old, and she was trying to figure out their connection because she was adopted out at the age of 6 weeks in 1949. My cousin, A, also in his late 60’s, was her highest match and she his on 23/me indicating a 2nd cousin match. He asked if I could help figure out their relationship in hopes of discovering her birth parents names. I don’t use 23/me, don’t really know much about it, but I am on GEDMatch so I got and uploaded their rawdata to see if B was also related to me (male-age 49). She was not. Since my cousin and I match through his dad’s parents (his gm is a sister of my ggm) I figured she must match him on his mothers side. I checked for a match at X and they have shared X DNA. I then tested one-to-many matches to see if they shared any other close matches. They did. Just one. A male, age 49, let’s call him “C”. Note; C has no X DNA shared with either A or B. He also was not a match to me.
    Anyway, I reached out to C for information only to be shocked by his answer that he had little info to share because he too was placed for adoption, but 20 years later than B, in the year of his birth 1968. He did have a letter from the adoption agency which provided him with his parents basic background, the mother’s physical description and most importantly her birth date.
    He did have an Ancestry DNA test which both he and my cousin A matched on and both also assigned me as the manager of their DNA tests so I could try and figure out who C’s birth parents were. B was also invited to take the AncestryDNA test (we are still awaiting the results). So cousin A & C had about 6 shared matches at 3rd/4th cousin, but C also had two 1st cousin matches that were unrelated to my cousin A. I contacted the closer matches and learned who C’s birth mother is using their info & their trees and his mom’s birth date. Through that connection I put him in touch with his new found siblings, some of whom are now doing the AncestryDNA to confirm C’s relation to them, before they broach the obviously sensitive subject with their mom. The agency letter made it absolutely clear that C’s father was not the father of these siblings. My search for C’s dad continued using the other shared matches at Ancestry with cousin A, since now we knew which matches were to C’s mom and that which remained as shared matches with my cousin A must be for C’s dad.
    Using those matches and researching the last two weeks I’ve finally discovered last night just how cousin A relates to these other matches. A’s great grandmother, on his maternal side, had 5 siblings; let’s call this whole bunch “Group D”. Each of the remaining shared matches on Ancestry between A & C lead back to Group D.
    Remember though, A, B & C all relate to each other at a 2nd to 4th cousin level, but only A & B have the shared X.
    Group D collectively, all born between 1870 and 1884, went on to produce over a dozen children of their own, collectively their issue begat children numbered in scores, and now I’m looking for a young male in his early 20’s in mid 1967 out of a group of just over 130 souls. Many of whom, despite weeding out those who are not male and not in their low 20’s in 1967, still leaves a sizable pool near 40 individuals and I’ve not found them all yet either.

    Questions I’m struggling with:
    Since A & B share X DNA and C does not, yet all are related, what’s the best way to learn who B’s biological parents are?

    Since B is related to A at the 2nd cousin level (higher than I am related to A) where should I look in my tree for her parents, before A’s grand parents birth or after?

    C’s dad…with such a huge field of candidates to sort through to determine who he is, is there a shortcut you could recommend?
    Here’s how all our DNA stacks up if it helps:

    My match to cousin A on GEDMatch is summed up as:
    Largest segment = 48.5 cM
    Total of segments > 7 cM = 159.1 cM
    8 matching segments
    Estimated number of generations to MRCA = 3.2
    No X DNA

    B’s match to A is summed up as:
    Largest segment = 54.9 cM
    Total of segments > 7 cM = 302.1 cM
    12 matching segments
    Estimated number of generations to MRCA = 2.8
    X DNA = 47 cM

    C’s match to A is summed up as:
    Largest segment = 28.4 cM
    Total of segments > 7 cM = 130.6 cM
    8 matching segments
    Estimated number of generations to MRCA = 3.4
    No X DNA

    C’s match to B is summed up as:
    Largest segment = 35.1 cM
    Total of segments > 7 cM = 147.2 cM
    6 matching segments
    Estimated number of generations to MRCA = 3.3
    No X DNA

  42. Boy are they lucky to have you on the case!

    The shortcut is to use GWorks, see
    After running GWorks, I look at the spouses’ surnames for each child and follow that line when the surname has some frequency.

    The older version of the DNAgedcom client also has a tool called match-o-matic which you can use to compare 2 match lists (the m_ files) for matches in common or different.

    By the way, I use this calculator to better determine the likely relationships (thus where to look on my tree)

    Having no X is meaningless except for close family relationships.

    Last but not least, check out the resources at

  43. Good afternoon. I received results today showing that my boys share 2425 cm. It also put them in the Full sibling, half sibling, grandparent category, which still leaves my question unanswered . I know it puts them on the high end for half sibs but on the low end for full sibs. I live in a country with a population of less than 400,000 and it is likely that most of us are related in some way. How can I get further clarity on this?

  44. Hello,
    I am a newbie to this. I did the DNA through Ancestry (xmas present) in hopes that I would find a half brother that I have heard I had. In doing so, my closet match came back at 2147 Centimorgans across 55 DNA segments. Her son came back at 1136 CM’s across 34 DNA segments. Her birth certificate shows different father but she was adopted. I have learned this from her son. I would assume from everything I read that she would be my half sister and her son would be by half nephew. I uploaded my results to GED match. I know its not from my mothers side and we don’t share the same matches from her side. Can you let me know what you think?


  45. Thanks for your reply. She was born in 45 and myself in 58. So 13 years. I asked if she uploaded. I just uploaded mine today. I will compare once I know. But just so I understand if she is my half sister, then the blue line will be there fully for the X , correct?

  46. I submitted a DNA test to Ancestry, more out of curiosity as to my heritage than to find anyone. But what I have come back with is VERY interesting. Bit of back story, my dad left before I was born, I did not find/meet him until I was 20. We lost contact soon after, and because of this, I do NOT know him or his side of the family well (his mother has gone so far as to hang up on me and refuse to acknowledge I exist.) So, not people I can call up to ask for clarification.

    But the DNA test came back giving me hits to people being close potential relatives, that well….with some digging, I am highly curious to know the actual relation to. My mom recalled my father’s mothers name, and her husband. Well, in the tangled mess of trees’DNA, I discovered that (I hope I can explain this properly):

    I share CLOSE DNA with a Lewman/Goodwin side of the tree, but on paper that would be impossible. Since my father’s mother is listed as her maiden name being Snapp, born in 1932. Her mother did not marry one Mr. George Lewman, until 1949. But, share DNA with a woman who links back to George’s maternal Uncle, and a man who links back to George’s BROTHER.

    I have also recently had confirmed (I vaguely recall my father mentioning it when I met him), that he WAS adopted by his mother’s husband. So, I always figured my father, born in 1951, was a product of her and someone else, then she married her now husband (last name Rasch), whom she had two other kids with in later years. BUT, I have uncovered an older brother, born in 1948, who’s father is listed as her husband, Mr. Rasch. So???? Did she have two kids prior to marrying him, that he adopted, or did she cheat?

    Or, as I am thinking, was the man her mother married in 1949, Mr. Lewman (who years earlier was married to her inferred father’s cousin, on the Snapp side. Tangled web, I tell ya!) REALLY her REAL father? Or was he possibly my father’s father? I am trying to figure this out, with no way of actually asking anyone for answers. I contacted the people who’s DNA link I shared, asking if they knew any info, and they never got back with me.

    So, here is the breakdown, on the Goodwin side, my DNA match shares: 229.2 centimorgans across 11 DNA segments.

    On the Lewman side, my DNA match shares: 75 centimorgans across 1 DNA segement.

    And I did find some Snapp DNA with someone who is listed as a possible 5th-6th cousin, sharing 34 centimorgans across 2 segments.

    So, I am hoping you can tell me who I am actually closest to, I am assuming the Goodwin line. Just HOW close, they said 2nd cousin. And just how I can find out who might be the father of my father…I don’t know? I just wanted to see if I could get some clarification, lol.

    Thank You.

  47. Ok my husband does not know who his father was. He completed Ancestry DNA and has a “Close family- 1st cousin” match come back at 1450cM at 49 segments. Do you think this is more of a half-brother, half- nephew or 1st cousin? The tree this person has listed we cannot find any matching surnames in the DNA matches trees from other individuals. Do you think maybe this person is wrong on who their father was? Or is it common to not find the surname of who he is eventually. I just cannot make a match between any of the trees on the 3rd cousin matches. Thank you!

  48. I cannot tell from the cMs alone but the likely relationships is one of the 25% ones, so uncle/nephew grandad or half brother. How many segments?

    Save a copy of the match’s tree (pedigree thief or take a text copy via )

    And then get in touch, carefully since it is probably a half brother see

    and yes he could be wrong about who his dad is. Have you used the GWorks technique to build down to your husband’s likely grandparents?

    Have your husband upload to GEDmatch in case his match is there. You can tell from the segment sizes which relationship is most likely.

    good luck!

  49. Hi Kitty,
    What does a white perpendicular line between 2 segments in the 2-D chromosome matching chart. Its referred to as an “old match”
    Many thanks,
    Jo Treston

  50. Hi Kitty, my mother had relations with two brothers and I’m not sure which is my father. I found a daughter from one of them and she agreed to take 23andMe with me. She came back at 19.5%, 1449 cM across 37 segments. How conclusive is this to say what relation she is to me?


      • Thank you Kitty. If I was tested on 23AndMe v4 chip and she was tested on v5, should I anticipate the % shared, segment length, total cM, or number of segments to change?


  51. Kitty you once helped me above with the A,B,C group…but now a new mystery has begun.
    First an update: We still cannot find the missing link between A, B & C but we’re okay with that for the time being, we are on the right path and we’re sure an answer is coming soon. C is in touch with his bio family and I’ve reunited B with her bio family and everyone’s talking in private chatrooms on facebook. So that worked out, however…poor B. Even though I found her bio mom’s family and put her in touch with half siblings on that side, the family on her dad’s side, has been harder to figure out.

    So far we’ve only determined the family she came from which consists of 5 siblings (4 males/1 female). My thought is that one of the 4 is most likely her dad and if not then the father of the 5 is. I’m in touch with the children of the 5, all of whom are over the age of 42 and they’ve all been a great help! So far two of them, both female, have taken AncestryDNA tests (one belongs to the child of the female, the other is the child of one of the males. They both match B at what seems to be 1st cousin. And here is where I get lost in the weeds:

    The two known cousins, let’s call them D (child of a male) & E (child of the female), on Ancestry, match each other at ‘1st cousin’. When I run the comparison at gedmatch I get these numbers:

    D & E: Largest segment = 68.5 cM
    Total of segments > 7 cM = 824.3 cM
    27 matching segments
    Estimated number of generations to MRCA = 2.1

    D also has an X match with E:
    Largest segment = 77.0 cM
    Total of segments > 7 cM = 87.2 cM Actual.

    When I run B & D:
    B & D: Largest segment = 123.0 cM
    Total of segments > 7 cM = 1,192.1 cM
    34 matching segments
    Estimated number of generations to MRCA = 1.8
    D also has an X match with B:
    Largest segment = 42.0 cM
    Total of segments > 7 cM = 79.4 cM Actual.

    When I run E & B:
    E & B: Largest segment = 77.2 cM
    Total of segments > 7 cM = 816.5 cM
    35 matching segments
    Estimated number of generations to MRCA = 2.1
    There is no X match between E & B

    So the questions I have are:
    1. Why is it that there is no X match between E & B when there are X matches with D & E and D & B if all are 1st cousins?

    2. Is there a good reason why B and D tested out as a higher match than E & D and E & B? 1192cM vs 824cM and 816cM respectively

    3. If in fact B’s father turned out to be the grandfather D & E, that would make B a half-aunt of D & E, do any of the result I’ve displayed here so far rule that scenario out as a possibility?

    4. Do these results indicate anything to you that I might be overlooking?

    Thanks a bunch

    • To answer
      1. Why is it that there is no X match between E & B when there are X matches with D & E and D & B if all are 1st cousins?

      Random. Do not worry about the lack of an X match, ever. This only eliminates sisters with the same father who must share the full X. I have even heard of rare cases of full siblings (2 boys) with no matching X.

      2. Is there a good reason why B and D tested out as a higher match than E & D and E & B? 1192cM vs 824cM and 816cM respectively

      No, DNA gets more and more random after very close family. Note that males will do less recombining of there DNA so it is normal for the child of a male to share larger segments with B. Both totals are solidly in the first cousin range, use this calculator

      3. If in fact B’s father turned out to be the grandfather D & E, that would make B a half-aunt of D & E, do any of the result I’ve displayed here so far rule that scenario out as a possibility?

      That possibility is not ruled out at all. To rule it out you would need good autosomal matches to the grandfather’s wife. If there are none, try target testing a descendant of one or more of her siblings. If no match then yes it is the grandad.
      If you can test a child of every son that would be best of course.

      4. Do these results indicate anything to you that I might be overlooking?
      Use the are your parents related on B to be sure they are not
      and see the ansewer to 3

  52. I just scrolled up and saw a reply you left for Andrew and at the end you left this line that caught my eye:
    “If (you) have at least 2 shared segments greater than 100cM then for sure she is your half sister”

    Is that a universal application or more specific to Andrew’s situation and the 1400+cM he and his half sister have?

    In my example above, where D matches with B with what Ancestry interpreted as a 1st cousin match, when I ran the dna for both on gedmatch using the 1 to 1 comparison, the reading was 1192cM and they DO have 2 segments over 100 cM. 123 and 115 respectively. I originally dismissed the idea of them being half sisters based on what I gleaned from another of your blog posts where you indicated ‘if two half sisters have the same father they would have a full blue bar on the bottom in an X chromosome 1 to 1 comparison on gedmatch’; Now I’m wondering if I misinterpreted that?

    Thanks again!

    • If they shared a father then they have to share a full X.

      Having 2 segments over 100 is a guideline to use when the total DNA is either a half sib or a aunt/niece relationship. See

      Yes D and B could be half sibs with a shared mother by the numbers but you are looking for the father, not the mother, right?

      It is very unusual for first cousins to share more than one segment > 100 and I have not seen this before. Is this population group at all endogamous?

      Now to answer your other questions.

    • Thank you for the replies! Combining my own replies to this single post:
      Yes, we are looking for B’s father. No, B’s parents are not related. Yes, I ran the DNA painter, but my post was so long already I didn’t want to add those results too. This is definitely not an endogamous population group.
      We are only able to DNA test a child from 3 of the 4 males; we are awaiting the last two test results now.

      Regarding the 4th male we only have access to 2 granddaughters, both are willing to take the test if needed, but I’m not sure what good their testing would do, since at best B would only test as a half aunt, at worst a grand aunt, to the pair?

      If neither of the 2 pending results is a conclusive half-sib match, we’ll then wait for the results of the granddaughters of male #4 at which time expect yet another glass of wine since I know I’ll need help sorting that out too. 🙂

      On the gedmatch ‘1 to many test’ I noticed that D, who is B’s top match, shows a total cM count of 1210, slightly higher than the ‘1 to 1 test’ at 1192; when using DNA Painter in such an instance should we use the 1 to 1 result or the 1 to many result or does it not even matter?

      Also, you mentioned you have never seen two >100 cM segments in a 1st cousin match, I’d be happy to privately share the kit numbers with you if you’d like to review the results directly. Email me and let me know.
      Thanks again!

  53. Yes test those grand daughters. The more tests, the easier to sort it out. Draw a McGuire diagram …. I will email you

  54. I find a match (MyHeritage) of 36.2 cM (on 2 segments, one on chromosomes 13 and one on 15, the largest segment size is 21.2 cM) with another who I suspect is an 8th cousin who is English. My American family descended from an English immigrant to the US in 1749. We suspect we have a common 8-9th English ancestor. Our American side has had no further contact with the English side as my “potential” eighth cousin’s family remained in England. Are the chances good that we have verified the family connection?

    • Thomas –
      No the chances are not all that good. I mark a match like this as a maybe. Back that far there can be other connections that neither of you is aware of.
      But then again, it could be. Perhaps you should both upload to GEDmatch, buy the tier 1 for a month, and use their triangulation function to see who else matches you two on those segments and whether they have similar ancestry ….

  55. Here’s what my mom shared with me.

    Mom and Dad were married 60 years
    Mom/Dad had one son together, J
    Mom had second son P; P had a different bio father (2nd man)
    Mom had daughter (Me). I had a different dad (3rd man)

    P & Me did 23&me. We share 30.8% of our DNA
    23&me says P is my uncle (since there were only 3 of us, that means J’s daughter. )
    Given that we most likely have the same mother but different fathers could we be 1/2 siblings?
    Or could my parents be mom and J?

    Mom/Dad/J are all deceased so we can’t do DNA.


  56. Can somebody please help me. I got a new match a few months ago. Shows as 1st. My family on Dad’s side 1st 2nd 3rd cousins aunts uncles all did their DNA. This man and I only share my kids as matches. So I am assuming his is from mom’s side as none of them have done their DNA. This is my question . We share 1046 centimorgans over 34 DNA segments. He was conceived in Kenya in 1952. Does this mean he is the son of one of my uncles from my mom’s side that was in kenya in the military. Someone please help. I don’t understand these charts

  57. I am totally new this DNA arena and need help. I just got my Ancestry DNA results back over a week ago. I have 3 close family matches. One I know is my mother’s sister with whom I share 1,645 cM across 80 DNA segments. Then there are two females that I have no idea who they are so I reached out and one replied back. She informed that the other match was her twin sister with whom I share 1,850 cM across 71 DNA segments. I share 1,569 cM across 65 DNA segments with her. ( I hope I didn’t confuse you)

    This would put them as possible half-siblings or aunt? They are 40 and I am 46 so I can’t see how they would be my aunt but then again anything is possible. I know my father has other children by other women. My match and I are baffled by this. My mother’s sister is not a match to these twins. My mother has agreed to take a DNA test but in the meantime, I am left confused.

  58. In the case of a half-sibling test,me,being male and Suzy being female sharing same father,showed 15.6 % relatedness.Would the Y chromosome be less prevalent in the female offspring?Is this percentage enough to seal the deal? Thanks

  59. Sorry Edward, my expertise is with personal genome tests like 23amd me or ancestry or … Those tests sample many many more data points than a simple relatedness test…

  60. I am so over my head with this DNA information. I had my DNA done on Ancestry in October 2016 and posted it on FTDNA & Heritage. No surprises in my DNA, 6 of my 8 great grandparents were born in Ireland, other 2 were from England. My results are also on Gedmatch which has been fun. I have a lot of numbers and am not sure which ones are the most important. I have 7 Gedmatch one-to-one comparisons in front of me. We all match on Chr 2, the cM go from 14.0 to 33.0 and all the locations are within the same range … 56,356,533 to 98,116,322. I have looked as several of their trees to no avail. Where do I go from here?

    • Sharon,
      If that is the only segment where you match these folk, it might be too far back to find. If one of the. Matches you in more places start with their tree and yours…

      I suggest you work with closer matches first. The ones with 90 or more cM and 3 or more segment, some of them large. Those relationships are generally findable

      And read a lot:-)..

  61. We received my husband’s dna results. His highest match is 1704cM. He believes this is with his first cousin: daughter of his father’s identical twin. But isn’t that number high for a 1st cousin? We are now doubting this is a cousin and wondering if this is a half-sister. How does identical twins and dna testing work? is there a difference in how we read the results?

    • The children of identical twins will look like half siblings in their DNA as one parent is effectively the same.So That result is normal for a first cousin fro. An identical twin.

  62. After sending my DNA to a woman showed up as a close relative who I had never heard of or met. After contacting her, she shared with me that she was adopted and didn’t know anything about her biological parents. She is related to me through my father’s side. My father shares 2265 cM with her. My dad’s full brother shares 1647 cM with her. I share 1107 cM with her so after looking at Blaine Bettinger’s The Shared cM Project I came to the conclusion that she was a half sibling to my father from an affair my grandfather must have had. This was not received well so I also had my cousin (my dad’s full sister’s daughter) send in her DNA to Ancestry to get more clarification and her cM is 1555. My dad’s sister has passed away and my dad’s father has passed away so no way to get their DNA. Now here is where I’m confused, 1555 cM can either be half sibling or full aunt but half aunt was not highlighted on Blaine Bettinger’s chart. How can I know without a doubt where this women fits in our family? Also, my dad’s full sister mentioned above was rumored to have given up twins for adoption but we don’t know for sure because she never told anyone. Lots of family secrets exposed!!!! I would love to have your input on this!

    • It would be best if you all uploaded to GEDmatch for direct chromosome comparisons. If people are uncomfortable with a public database, then upload to family tree DNA. Not quite as much information there and everyone needs their own account but it will have the X matching and the exact segments which may be enough to figure this out.
      How much does your father share with his full brother and the niece? Your cousin shares more than the expected amount for a half niece, more like a half sibling which fits that story.
      Does this woman have matches on your father’s mother’s side of the family? That would confirm her being his sister’s child.

  63. My father shares 2,443 cM and 63 segments with his full brother. He shares 2001 cM and 59 segments with my cousin (his full sister’s daughter). I am trying to figure out if anyone from my grandmother’s side is showing up on our dna match lists. I can’t believe i didn’t think of that! I am in encouraging everyone to upload their dna to GEDmatch today. I just find it so odd that my dad shares 2265 cM and 56 segments with this new family memeber. Thank you so much for getting back to me! Your blog is an amazing place for a wealth of knowledge.

  64. I had a match on Ancestry of a woman who was adopted by closed adoption. We are close in age. We matched 1111 centimorgans on 45 DNA segments.Is that high for a 1st cousin? My known first cousins match in the 888 range on 35 to 40 DNA or so. One cousin, is both my 1st cousin & 3rd cousin , the cousin range fell in the usual limits! Could she be my maternal uncle child? I had 2 uncles who have no living children and they are deceased as is my mother. My 1st cousins on that side matched her too we don’t know of any adoptions in the family.

  65. Yes she could be your maternal uncle’s child. Although high, that is in range for a first cousin.
    He may not even have known that she existed. If you both upload to GEDmatch you could take a deeper look at this and check the X match.
    How many siblings did your mother have? Is a child of every one of them tested (where children are available)?
    Pass this on to your new cousin

  66. I have a match on Ancestry “M” who shares 2135 centimorgans across 57 strands of DNA. I know we are related on my dad’s side as we have other matches in common (distant, but I can confirm their relationship to myself and my dad). She messaged me and said she matched as a first cousin to “E” and “E” is my dad’s sister’s daughter. We have come to the conclusion that we are most likely half-sisters as we are 2 years apart in age and some other pieces would fit this scenario. Is there any other possibility?

  67. I have used the calculator you have as well as one with dnaHunters.

    In each case my Uncle and the “cousin” on 23andme show up as possibly 1/2’s or 1st cousin 1-removed. They share 19 segments, 5.07%, and 377cm.
    It is through this match that we believe we may be able to learn about my Grandfather who was a bit of a mystery.
    This “male cousin” though is of Haplogroup R-m417 where my Uncle tested as R-Z159 – this is through 23andme (is 23andme good enough to calculate this?). However, none of the shared segments are on the x-chromosome.

    My uncle was born in 1933 – however my grandfather David was around 43 (we have 3 different possible birth dates 1887, 1890, 1893) which means he very well could have had children elsewhere. **IF the child he had with someone else was a girl who then married a guy then had the baby (cousin born in 1946) that could explain things.
    The more difficult part is that this “cousin” doesn’t seem to believe there is much of a connection as the surnames are different. But we are relatively positive that David changed his or something.

    Because my father tested as R-Z159 a thought of doing a yDNA test was suggested by a friend.

    • Yes, if the mystery is on a Y line then please do at least a 37 marker test and better a 67 since it is an R group. You can do this test at family tree DNA (do me a favor and use my affiliate link to buy it 0 )

      Often when someone asks this question, one R group (as listed by the end SNP) is downstream of the other so possibly the same group but that is not the case here. Your father’s Z159 is in the R1b subgroup while m417 is in the R1a subgrouping. Click on R on this page and then search for each SNP.

      So this male cousin is not on the paternal line with your mystery. Thus your idea “the child he had with someone else was a girl who then married a guy then had the baby (cousin born in 1946) that could explain things.” Looks likely. Find out more about your new cousin’s mother’s ancestry perhaps her father of record was not her bio dad or perhaps he is your mystery grandad … get more of his descendants to test

  68. Ms. Cooper,

    I tested through 23andme and matched with a a likely first cousin that I didn’t know about. We have since then contacted each other and exchanged enough information to place on his small town both a maternal uncle and half-uncle of mine.
    The only other of my family members that tested is my father and they share 0 DNA.

    I am trying to convince my mother or one of her full brothers to do a 23andme kit; but they distrust the procedure. They don’t have a problem with having a possible new nephew; they just don’t seem to understand how 23andme works.

    To summarize, I am pretty much convinced new cousin and I share a grandfather (my mother’s father). I’m just trying to figure out if I should completely eliminate the possibility of us being full 1C.
    We share 590cM, accross 22 segments. With segments of less than 7cM removed, we share 577 cM. We also share four segments over 50cM:
    53.89, 53.99, 64.88, 85.06
    What do you think about this data? I know the numbers are on the low side of full 1C; but I have uncovered a lot of coincidences around that match being likely.


  69. Hi Kitty,

    My dad and sister both had their DNA done by 23 and me and discovered a previously unknown close relative named Mary. Mary shares 27.1%, 2016 cM with 37 segments with my dad and 14.4%, 1073 cM with 28 segments with my sister.

    23 and me listed Mary as my dad’s granddaughter and my sister’s 1st cousin. Mary contacted my sister and said her mother was born in 1933 and at one point her mother told her that she had a different biological father than the dad who raised her.

    My dad was born in 1925 and is obviously not Mary’s mom’s dad. My dad did not have kids until starting in 1958 that we know of. It’s possible he had a son who fathered Mary but given the age differences we think it’s highly unlikely.

    More likely is that my dad is Mary’s uncle and she is his niece as well as my and my sister’s 1st cousin. My father had 6 brothers but the oldest two were half-brothers from his father’s first marriage. They cannot be Mary’s father given the DNA shown above. My dad also had 3 full brothers who could be Mary’s father.

    The problem we have is that my dad’s mother also had another son out of wedlock before she married my grandfather. That son’s name was Dennis and his father was his great-uncle and his mother’s uncle.

    Can Dennis be Mary’s father? Or can we rule him out? He was more than a half-brother to my father biologically but how does that translate?

    Thanks for any help you can provide,

    Joe D

    • You really need to test more cousins to get the answer to this. It is not impossible that Dennis is her Dad, although highly unlikely as the shared DNA would usually be less (around 1300-1600), so likely it is one of your Dad’s brothers.

      Are any cousins on your mother’s side (1st or 2nd) tested? Your father’s side? You may need to compare them to Mary to find your answer. If the possible Dads cannot be tested, get a child of each to test if you can.

  70. A few months ago I signed up for Ancestry and when my DNA came back there was a “first cousin” match with 900cm. This gentleman lives over 2,500 miles away from my family here on the US’s west coast, and his parents and their ancestors were from a very small farming community and didn’t travel. He is my parents’ age, about 70.

    I have confirmed DNA matches to 7 of my 8 great-grandparents. (One great-grandma came from a very remote UK island and was a recent immigrant — she’s the one I don’t have matches with yet.)

    My mystery “cousin” believes that he must be my half-uncle (other relationships don’t make sense) and that his father must have been one of my parents’ fathers. Given birth dates and distance, I can’t see how that could be so. For the same reason, he cannot be my cousin. It IS remotely possible that a paternal grandfather or great-grandfather of mine, who were known to have done a little business travel to the midwest, could be HIS father, or grandfather. But he insists that he has DNA links to all four of his grandparents. But so do I, and more.

    Complicating matters, about 5 generations back we do have a shared ancestor on our paternal lines, and I suspect that there may be a few more of those as we dig deeper. In the 19th century, some of my ancestors lived in the state where he’s from (although not in that county) and our trees do share a few surnames (though not very recent ones).

    Is it possible that a DNA match with 900cm could be anything but a half-uncle or half-great-uncle to me? Could the large amount of centimorgans possibly be due to multiple shared ancestors farther back? I’m thinking, maybe he’s something like a second or third cousin (though I don’t know how yet) and the rest of it is due to sharing some DNA due to more distant shared ancestors. Is that possible?

    I don’t know if you have time to reply to this long comment. In any case, thanks so much for this marvelous website; I’ve learned so much from you!

  71. Have been looking for my brothers bio father for years. He recently tested with Ancestry and his closest match is with a woman who shares 1511 Cm’s. Her maiden name is the same as several of his male matches on FTDNA. He also matches another lady who is a niece of his 1511 match. this match is at 1094. Am I to assume that the 1511 match is his half-sister. They all live in the same state.

  72. Greetings Ms Kitty, I have what seems to be a complicated question.
    I am looking for a DNA relationship connected to my four times great
    grandmother. She was an immigrant from County Tyrone Northern Ireland. I just found a descendant from a family with the same surname who also immigrated from County Tyrone at about the same time and settled in VA. Therefore we are looking at small amounts of DNA from relatives who were born in the 1770s. We are both in GEDmatch and I also have the DNA of my sister and a distant cousin of this line in GED. When I compare our Ancestry kits, no relationship comes up, but when I compare our three Ancestry kits to his second kit via Family Tree we get a bunch of hits at the 3 CM and 2CM levels. ie my sister matches him on 5 chromosomes at levels of 3.6, 4.2, 4.6, 3.1, and 3.2 CMs. My matching is a bit less and my distant cousin matches only at the 2CM level. So, my question is, what does all this mean? Why matching with Ft and not Ancestry? Is this relationship real or just noise? I hope all of this makes sense and I really appreciate any help and answers. thanks so much

    • At that distance of relationship autosomal DNA is not very reliable. You might be better off finding a straight maternal line descendant on each line and doing an mtDNA test although since that can go very far back in time, it only answers your question when they do NOT match.

      Ancestry removes population specific autosomal DNA matching while family tree DNA shows very small and not necessarily relevant matching segments.

      Most segments smaller than 7cM are not real matches so we tend to ignore them. Even if those small segments that your sister shares are also shared with you and/or your cousin (triangulation), they may not be meaningful.

      see this post for an explanantion of false matching:

  73. many thanks for the quick answer. not sure that we can find any straight maternal line descendants. guess we will just have to work harder
    on paper relationships. possibly not that many gibboneys in county tyrone in the 1770s. bill

  74. A 4th grandparent is just too far back for reliable autosomal results but if you get enough of her descendants tested, preferably the older generations, you may be able to get somewhere …good luck

  75. Hello Ms Cooper,
    I just filled out your questionnaire at the bottom of this page. The popup after I submitted says “half sibling or aunt/uncle or grands (doesn’t apply due to age difference)?”

    My match is someone Ancestry said was a likely 3 or 4C, who was adopted in 1958 and whom I have just started helping to find her birth mother. Am I misreading, or does this popup mean she could in fact be my half-sister? Thank you for your help!

  76. Miss Kitty, I have another question for you. My cousin and I are related via two brothers who are our great grandfathers. In Ancestry we only share 8 centimorgans and I know that that low level is possible for this relationship, but not usual. The problem is that we are more related than that. His great grandfather married his first cousin. That first cousin was also a first cousin of my great grandfather. She was the daughter of their maternal aunt. I am wondering if there is something wrong in our assumptions about parentage? I share many more centimorgans with
    several other cousins within this family who are descendants of other great grandparent siblings. The largest amount is 109 centimorgans. thanks so much again, Bill

    • William –
      So you are 3rd cousins plus 4th cousins on that family line. That low an amount is unlikely but possible, DNAPainter says it is 6.87% for just the 3rd cousin relationship.
      Of course, another possibility is that your cousin’s great-grandad’s father is not his biological father. Check if your cousin matches people on your side of the family and other great grandparent siblings not married to any cousins of theirs. Again, it could just be the randomness of DNA.
      If your cousin is not matching people just related to his g-grandad’s father’s side perhaps if you are both male line descendants of those brothers, a Y test will answer this question.

  77. Thanks so much for the quick answer and the ideas to check DNA
    relationships. This cousin will freak out if he thinks that he has carried
    the wrong last name since birth. I will have to be careful how I
    research this and let him see the DNA issues on his own. Bill

  78. Hi Kitty,
    I really enjoy your blog and all the DNA problem-solving you are able to do! I’ve bought you some wine as I need your expertise on something 🙂

    I’m helping someone with their DNA testing. This lady aged 84 (tested at 23andMe) has a new match on Gedmatch, a lady aged 85 who tested on (Ancestry). At first I thought first cousins but it could be a half-aunt? The grandfather had 5 sons and was then was widowed and needed a housekeeper.

    There is no shared X dna, so they are not sisters. Is that correct?

    They share 1015 cM across 17 chromosomes, some of it in very large chunks, including near total coverage of chromosome 22! The longest segments are 133cM on chromosome 12, and 128cM on chromosome 13 with some other chunks being in the 60s, 70s and 80s.

    When the ladies compared photos the likeness was uncanny. As one said “Like looking at a photo of myself!” One lady has known family history, the other didn’t know who her father was.

    The ladies are both excited to have made the connection and are planning to meet up. I have told them they are paternal first cousins but am I correct?
    I know the shared amount falls into both categories of yours and Blaine’s relationship analysis.

    Thanks so much 🙂

  79. The large segments would argue for the closer relationship – half aunt but she could also be child of one of those many sons.
    To figure this out it would be best to test each son (or a child of each son). The lack of X is never as conclusive a piece of evidence as having an X match. However it again argues for the half aunt scenario since both ladies would get X from their fathers and if their fathers are brothers it is very likely that they would share some X although not a for sure thing. for example I share 120cM with a first cousin whose Dad was my Dad’s brother…

    • Thanks Kitty. Will look into testing other paternal-side cousins.

      Even if nobody else tests, at least this lady now knows her father came from that family.

  80. Hi Kitty,

    I have a question regarding Y DNA. I’ve tested my Uncle out 111 markers, most other men have yet to test out that far. At 67 markers he has 5 matches with zero deviation, so 96% approximately they are related within 6 generations. I get that part. In corresponding with these men, I found one that has the exact same matches in common, with the exact deviations at this level of testing, neither of them has an additional person. Does this have any additional significance possibly suggesting a closer relationship?

    • I am not sure I understand your question. If they are 0 step matches then they should all have exactly the same matches as each other. This is a GREAT set of matches. The common ancestor should be findable in genealogical time.

      I have an R1b cousin who has a 0 step match that shares an ancestor born in 1603 while my Dad is a 3 step match on his line from a common ancestor in 1610. So this can vary widely but I would expect a 0 step match to be more likely recent, within 200 years.

  81. Do you know how to determine the chromosome analysis where two individuals have the same father, different mothers, but the mothers are sisters?

  82. Hi Kitty,
    I have a question regarding second cousins. On my grandfather’s AncestryDNA account, someone who should show up as a second cousin shows up as a third cousin with 171 shared cMs. They both share the same g grandfather. I noticed he also had two second cousin once removed matches that show up with the “correct” amount of cMs for that type of relationship. All three of these matches are descendants of the same son of this g grandfather (my grandfather’s g g uncle). It doesn’t seem like they share any other ancestors, and my grandfather also has matches with more distant cousins from that same family line, most notably in regards to his third g grandfather. Does this just have something to do with the Ancestry algorithm, or is there another explanation?

  83. I am wondering if these results show a 1/2 nephew, my 1/2 sisters son
    13.1% match, 931 mg across 31 segments, 120 being the largest, thanks for any insight

  84. Hi Kitty,
    My dad grew up knowing that he had a half-brother (same father). They never met as their father died when my dad was only 2. I made contact my father’s half-brother’s granddaughter some time ago and this past year we each did an Ancestry dna test. We did not show up as matching at each other. So, we each had our fathers do the test. Our fathers do not match each other or us. We do have several shared matches- people who match some or all of us. Is it possible for a half-nephew & half-uncle to have no shared dna? Thank you for your thoughts!

  85. Hi – I have a question please. When I did my DNA I found out my father who I lived with all my life (I am 70 now) wasn’t biological father. My biological father is Greek. I have many Greek matches. My highest match on Ancestry has no shared matches with me. However, my next highest match (and many of the others all match each other), Is it possible for a 2nd cousin to have no matches with my other Greek matches (3rd or less generations).


  86. Hello. I found out 2 years ago through DNA testing that my biological father was not the man I believed was my father. My mother took the answer to her grave but recently a very close match showed up on 23 and me. He shows up as an X match but does not share any DNA with known relatives to me on my mother’s side on this site. He shows up as a first cousin but I believe he may be the son of a possible half sister. He matches me 17% over 32 segment, not as close as my half sister but closer than a half niece. Am I wrong to suspect his mother could be my half sister on the paternal side? Would other scenarios make more sense? The ages of my match and his mother would work.

  87. Found two siblings that according to AncesterDnA share 1955 centimorgans across 67 elements. CEDmatch show that they share 2049 centimorgans. Babtisme certificate confirms that they have the same mother. Are they likely to be half siblings or could they be full siblings.

  88. Trying to rule in or out a hunch regarding my great-grandparents. My great-grandmother was ‘widowed’ to a man with the same name as the man who later raised a family with her sister. I am trying to determine if this is a coincidence, or if my great-grandmother and her sister both had children to the same man, who maybe didn’t widow her but rather left her for her sister. My father and I were both matched by DNA to descendants of my great-grandmother’s sister, who I suspect to be mother and child. Below are our matches through Ancestry…do you think these matches support or refute the mystery of my great-grandparents?
    My father matching with the mother: 345 cm over 18 segments
    Me matching with the mother: 231 cm over 14 segments
    My father matching with the child: 213 cm over 13 segments
    Me matching with the child: 178 cm over 11 segments
    I have found with other matches that I share with my father seem to reduce by almost half, whereas the above matches do not. (see example below) Can any conclusions be drawn by this data?
    Other matches: With my Dad – 532 cm over 30 segments, same person matched to me – 264 cm over 18 segments

  89. a man was adopted, and his children are all emailing me thru 23andme to find out why my dna is so high (26%) sharing with their dad and them (less percent). i have NO idea. i dont even know how we could be related and since his adoption records are closed, i have no idea how to investigate. his children are all half brothers and sisters to each other. whadda mess! please help!

  90. Mike –
    With that high amount shared you could be the adoptees half brother, or his uncle, or a nephew if he is a full sibling to one of your parents. What are the relative ages of the people involved?
    See this article about 25% relationships
    The best way to help is to send them your family tree and get a few more of your relatives to test – a paternal and a maternal cousin. Also send them this url:
    These cases are very solvable with DNA and you are their key. It is good that you are willing to help.

  91. I was just contacted yesterday by a gentleman that popped up on my ancestry DNA match as close family. Our match shows as 1367cM on 42 segments. He was adopted, but has the family tree for his “biological” parents, but i am not finding anyone in common with my own. I know it is on my dads side as we both match up with my dads cousin. I match with my dads cousin as a 2nd cousin with 261cM on 9 segments, but he matches with her at 94cM on 4 segments showing 3rd cousins.
    I believe that the man he believes is his biological father is not really, but i have never known anyone on my dads side besides his cousin…. not sure how to proceed with this puzzle. I asked my dad to submit his DNA for testing to compare the relationship if the two.
    Thank You

  92. We have a family mystery that has been ongoing for 70 plus years. My husbands grandmother had a baby at the age of 16 (no father was ever listed). I recently discovered that she may been raped by a family member an Uncle. There is a close match to my husband and the Uncle’s son. Amount of shared DNA is 238 centimorgans across 12 DNA segments. Not sure how to read this… Ancestry says 2nd cousin….

    I hope I am wrong about this and the information given to me is incorrect…

  93. Hello Kitty,
    Great to find this page. It is an interesting time in our family with me doing the family tree in detail and my daughter and son doing their DNA tests.

    My daughter’s test is back and we found an interesting link that we are exploring.

    We have a 300 cM across 14 segments link to another person from a lineage that I recognise in my family tree.

    The overlap is at my grandparents level. Here is the question I have to hopefully get your insight on (trying to see what the likely hood is).

    My grandfather was the first child in a very short marriage. My great grandmother divorced and re-married soon. The link from Ancestry seems to point to what I would consider to be one of my grandfather’s half sisters, or one of her children.

    However, with me not understanding enough about cM’s and sectors, I am starting to wonder if they were in actual fact full brother and sister (to make the number to my daughter so high).

    If that is still too high, I am starting to wonder if my mother maybe was handed sideways to care for (by one of the other girls of her generation in what would have been family attached through the same mother).

    How would you interpret the numbers? Or at least, what option could we exclude because the numbers are too high for certain options?

    Thank you so much in advance.

  94. I’ve done ancestry DNA test and compared at gedmatch. My little sister and I are trying to figure out if we have the same bio father. Our mother is the same but we want to know if we share the same dad. Is there a way to know this without his DNA? He’s dead and we don’t know his children from his 1st marriage so…..

  95. I have read through all of these comments, Kitty, you are amazingly helpful and so knowledgeable! I am struggling to make sense of the following results I got from 23andMe. My grandniece, my sister’s granddaughter, registered as a 4% DNA match across 13 segments. This is low for a grandniece/aunt relationship, which registers usually 12.5% So I am wondering if my sister and I are really half-siblings. Further support for this is that my grand-niece registers as a distant cousin for many of our mutual “relatives in common” (one confirmed 2nd cousin on my mom’s side, but doesn’t register at all for others (for those who I think may be 2nd/3rd cousins of mine on my Dad’s side, she doesn’t register as a “match” at all).

    I know that unless my sister gets a test done, we may not know for sure, but is there any other way to interpret what I have described? I guess I am wondering if there is any other explanation for such a low percentage for a grandniece and for her not showing as a relative in common with so many of my matches. Thank you for any insight!

    • Rose
      It sounds like you are interpreting the results correctly. If you get a first cousin on your father’s side to test and he does not match your grand niece that would be pretty conclusive. Obviously your sister’s test would be better!
      Use this calculator, it will take percentages

  96. Thanks for this. It kind of makes sense, but it’s going to take a while to process.
    I’m trying to figure out if a person is a half uncle or not. He can’t be a great-uncle, because my great grandmother was already 64 when he was born.
    23&Me has him at a 10% match with me, and 747 cM
    While the same person is a 6.47% and 482cM with my 2nd cousin.
    He’s also 14.4% match with her father, and 8.91% with her 1st cousin.

  97. This should help…

    And here’s more background…
    KD is the person in question.
    BW is my mom’s 1st cousin.
    KW is his daughter, and SS is his niece (brother’s daughter).

    Based on the numbers KD is BW’s 1st cousin. But it seems to me that KD is too closely related to me to be a 1st Cousin once removed, and it’s impossible for him to be a Great uncle, which leaves him being a half-uncle/my mother’s half-brother…. right?

    • Ed –
      I apologize, I am very busy this week and answering a complex question like this takes more time than I have. Your reasoning seems sound.
      You could test more family members to try and narrow this down some more. There is always a certain amount of randomness in total DNA shared.
      One other thought, if he is your mother’s half brother, you two will share the same mtDNA haplogroup which 23andme will show you. Is that the case?

      • So I took the Ancestry test as well, and the results are similar. We have additional cousins there (1c1r) who’s parents were siblings to my grandmother. Their relation to KD and me are in line with BW.
        KD and I do share mtDNA H1, but from what I’ve read, that could also mean his mother and my grandmother are sisters. My GM was one of 7 sisters. Plus I read that H1 is pretty common too.
        I was able to rule out a couple of the sisters due to where they were living at the time, or the fact that they were pregnant with other kids at the time.
        At this point I’m pretty close to certain it was either my grandmother or one other sister, who supposedly never had any children.

  98. hi My Mom and I took a dna test on ancestry last year my mom does not know her biolagical father except that his last name is Fisher earlier this year we got a match that said close family his last name was Jones on my mom’s test and 1st cousin on mine she does not want to contact him AND I don’t know why she shares 1,891 cM across 49 segments and he shares 847 cM with me I looked at the Cm chart and I know he could either be a grandparent an uncle a nephew or a half brother to my mom he is in the 50-59 age range and my mom is 53 could be a half brother if so then why isn’t his last name fisher could it be possible that my mothers biological dad’s last name isn’t Fisher if he isn’t a half brother then what could he be thanks ?

    • Eric –
      Make sure that Mr Jones does not match any relatives on your mother’s side. Given that he does not, then your assumptions are correct, he is a paternal ” uncle, nephew or a half brother” based on the relative ages. Obviously a half brother is the most likely scenario and I can not tell you how many times the surname of the unknown Dad is not what the person was told by their mother. Another possibility is that he is using a fake name at Ancestry.

    • Eric –
      My mother didn’t know her biological father either. My grandmother was pretty tight lipped about the situation. She just said he died before my mom was born, and we left it at that.
      As I started to research to find out who it was, I learned that, back in those days, it was normal to not list the father on the birth certificate, if the mother wasn’t married to him. This was true even if it was known who the father was, and he was involved in the whole thing.
      This explained to me why mother had the same maiden name as my grandmother. I would have thought that if he died before her birth, then they might list him, but they didn’t.
      Aside from that, thanks to the DNA results, I too found close relations and distant ones, and was able to determine who her father was, and that he didn’t die before her birth, but in fact got married to another woman that year, and had child with her 6 months after my mother was born, and a few more, and died in 2009.

  99. I love all this information and like many others found a man in my DNA Matches on who I have never heard of. Our match looks like this: Shared DNA: 1,554 cM across 47 segments. I am 55, he is 42. He also matches a known 1st Cousin on my dad’s side: Shared DNA: 682 cM across 37 segments. In addition, he matches up to 12 pages of other DNA matches on my dad’s side. says he is close family to first cousin. I am believing from what I have read here that he is a half-sibling. Would you agree?

  100. I want your opinion on what is the maximum period(years, generations) to the common ancestor I share with some 3 people. The common thing between me and these 3 people is that we are 4 people who all share a 18.8 cM large single block between each other. But some of us share also further segments. My raw data is from FTDNA and unphased.

    My relationship to my 1st match(according to my testing company, the furthest we can be is 5th cousins):
    Shared DNA: 0.5% (34.6‎ cM)
    Shared segments: 3
    Longest block: 19.9‎ cM
    My 1st match’s relationship to the other 2 matches: 0.3% (18.8‎ cM) and 0.4% (25.8‎ cM)

    My relationship to my 2nd match(according to my testing company, the furthest we can be is 5th cousins):
    Shared DNA: 0.5% (33.2 cM)
    Shared segments: 1
    Longest block: 33.2 cM
    My 2nd match’s relationship to the other 2 matches: 0.3% (18.8‎ cM) and 0.4% (27.1 cM)

    My relationship to my 3rd match:
    Shared DNA: 0.3% (20.3‎ cM)
    Shared segments: 1
    Longest block: 20.3 cM
    My 3rd match’s relationship to the other 2 matches: 0.4% (25.8‎ cM) and 0.4% (27.1‎ cM)

    • Sorry, once you get past close relatives, due to the randomness of DNA you cannot accurately predict the relationship with smaller matches. Also you have to remove segments less than 7 from the ftDNA totals.
      Best to keep working the trees looking for common ancestors who can be very far back. I have have a triangulating segment like this from the 1400s (still looking for other connections!)

      • Thank you for the reply. Is this triangulating segment from the 1400s longer than 7cM?

        I don’t have known family links with the matches. My matches above are in MyHeritage. It is very strange that I and my match uploaded our data correctly to Gedmatch Genesis we did not match like that, like the segment dropped from 35cM to 7cM. But I still match others with 23cM in both MyHeritage to Gedmatch Genesis. I referred to this article but I didn’t find the answers:

        Can I ask one last question – are MyHeritage matches who don’t appear in Gedmatch legitimate?

        • insginio, my Dad and brother’s triangulating old segment is from about 45M to 68M on segment 2 ranging from 8-22 cM with most from 10-14cM
          As to MyHertitage, each company uses slightly different algorithms to accomodate the different chip sets. Try checking the “prevent hard breaks” box at Genesis when doing the one to one comparison. Also dropping the cMs to 5 (known matches only) sometimes helps.

  101. Although I submitted a form, I couldn’t answer all of the questions. But, here are answers for questions not asked.

    I have a DNA match on who doesn’t seem to appear on other DNA websites where I’ve uploaded my raw DNA data to. (,,, etc). We share 1,742 cm and 73 Segments. Due to our shared matches, I know we would have to be related on my paternal side. We share Puerto Rican Ancestry. My father was of Puerto Rican descent. My mother is of African-American Descent. It shows this male and I share some 2nd and 3rd cousins, but unfortunately they have not responded to any of my messages. It’s really frustrating. My father, mother , and all grandparents except one are deceased. My father’s mother is still alive. I never met or knew anything about my father’s father. I was just reunited with father’s mother 2 yrs ago. She told me my father’s father died before I was born. She says he and my father shared the same name. However, like my father, I haven’t been able to find any records on him. I know my grandmother had two children with my grandfather, but both my father and his sister are deceased. My grandmother will not take a DNA test. She is old school and doesn’t believe in this technology. Lol. She is very suspicious. But, through DNA matches of 3rd and 4th cousins I was able to confirm that we are all related through my grandmother’s aunts uncles. What can I do to figure out how this male and I are actually related? How do I decipher who’s related on my paternal or maternal side just by the DNA? I have had a hard time understanding many of the articles that may or may not discuss this.

    • Try to convince her to test as a big favor to you.
      So at 1700 he is either a half brother, an uncle or a nephew (since grandfather is out). Are you in touch with him? could your fathar have had a child with another woman besides your mother?
      If you have a name for him you might try googling it or using a people aseacrh site to get in touch.

  102. Hi Kitty,

    Thru DNA we discovered a previously unknown close relative named Mary. Mary has 27.1% DNA with my Dad and 10.9% with my sister. My Dad had 3 brothers one of whom must be Mary’s father. Two of the brothers had no kids we know of and are deceased. The third brother had four kids and one of them (John) took DNA test and was 15.8% related to Mary. The DNA painter tool says there is only 12% chance he and Mary are half-siblings but John and Mary share 45% more DNA than John does with my sister (also 10.9% match) and 62% more than John does with another female 1st cousin (9.76% with daughter of my dad’s sister). How significant is it that John shares well over 50% more DNA with Mary than he does with his two known female 1st cousins? Does that raise the odds that John and Mary are really half-siblings or is it just random? Any help would be greatly appreciated,

    Thanks Joe

  103. Hi Kitty,
    I was adopted w/very little information about my birth family. I have a “close family” DNA match on Ancestry with a woman who has 1,479cM and 61 seg. She is about 29 years older than me, with one brother, no sisters. She and her family grew up about an hour and a half away from the Mother’s Home where my mother stayed while pregnant. We are trying to figure out if her brother could be my father. Do those numbers seem logical? It seems to be the most obvious answer considering the numbers, but what are the other possibilities? She can’t seem to trick her brother into taking the test “just for fun”. Thanks!

    • Yes, by far the most likely explanation is that she is your aunt. Are any of her cousins tested? Has she shared her DNA with you so you can compare how she matches to how you match, to see if that fits your theory?
      Perhaps suggest that she tell her brother why he should test. There was less shame for men in these situations…

  104. Thanks! I am very new to this. I’ll ask her if her cousins have been tested, but I did notice that I am a distant relation (3rd cousin’ish) to a man who shares the same last name as she does (and her brother), so that leads me to believe that we are looking in the right direction. I did just change my settings on Ancestry to share my dna with her, and emailed to see if she’d do the same. We are having lunch next week, so I’ll bring up having the discussion with her brother. Thank you!

  105. Hi Kitty,
    Wow, for all the help you’ve provided everyone on this site. Thank you for that. I think I have a simple question but you can tell me.
    I have my DNA, my half sisters DNA (1877cM) (through my mother) and my aunt’s DNA(2003cM) (through my mom). My half sister and aunt are not related to my BIO dad and I’m trying to find my BIO dad. I recently got a match on Ancestry possible 1st – 2nd cousin (507cM across 26 segments). Ancestry doesn’t detects that this person does not share DNA with my Aunt or half sister which makes me believe that she is possibly related through my BIO dad. Is it possible that the match could be related through my mom’s line but not share any DNA with my half sister and Aunt? I am trying to eliminate the possibility of a relationship on my maternal side.

    • Correction.
      * Ancestry says this person does not share DNA with my Aunt or half sister which makes me believe that she is possibly related through my BIO dad

      • A match that close would surely share with your Aunt or half sister if it was on the maternal side, so yes you can assume on your dad’s side. Save all the information if they have a tree before you contact them just in case … sometimes people get freaked out by the possibility of infidelity in their family and remove their information

        On the bright side look at the matches you share with this match. You may well be able to figure it out now. Read up on the methodology for adoptees, when one parent is known, it is much easier, see

  106. all my life I was told my father was James Daniel English from San Antonio, tX. I have searched and searched. I even got a letter from a woman that said Honey my husband is Jimmy Daniel English, I threw the letter away months later I made my mom made she said Honey Jimmy was a contractor from san antonio, TX he put cabinets in remodeled homes. Never told her about the letter not even to the day she died. I took the DNA test, NOT ONE English on the list. but it said I was from Clemans, from Ohio where mom was from, I was born. So I am doing search’s. also it said two women are first cousins, i did your blog and it said 1/2 sister, aunt, uncle grandmother. I hope to find more. I wrote them but they never answered me.

  107. A young lady approached me stating our DNA had marches. This was through Ancestry DNA and it showed we have 1618 cm across 72 segments. I believe she’s my neice but my one brother is deceased. My other brother has refused to take a DNA test, so I’ve asked my nephew if he would take the test. Yes, if it’s a reputable company. I have accepted her as my neice. Now another part, a guy contacted me stating he’s been doing his dad’s DNA ancestry. He came out and said it appears to him that my great grandmother had sex with a 14 y.o. boy. I said I felt he was reaching. My hubby made a 10 generation notebook , on both sides. I know it took him a long time because my mom was from Holland. I went over this notebook again and told him I didn’t see any Mannings directly in my genealogy. However, I told him my hubby included the names and dates of the women who married into the Tiger family including their parents and siblings. I also stated I thought I could say we were related through my great, great, great, great, great grandfather’s side because that’s when I started to see some names of people we are related to, including the Apgars and Alpaughs. His father and I share 270 cans. So, who is correct? This guy thinks his dad and I are 1st or 2nd cousins. I told him I knew all of my 1sr cousins, although many are deceased now. Please help me with this, as I’m confused and my living brother and sister have thrown me out of the family. Thank you so very much for your help! Sincerely, Martha Tiger-Ochs

    • Martha –
      His theory is just that, a theory which sounds rather dubious. Yes that amount of DNA is most likely a 2nd cousin or a 1st twice removed or possibly a half 2nd cousin. certainly he is a close relative.
      Use this calculator to see
      Does he share DNA with your niece, how much? Any other relatives? Basically one builds a case based on the total matches to your family/ Could your great grandmother have been 12 or 13 when this happened? Out of wedlock births are not necessarily well documented so would not be in that book. Things did happen.
      If you are really upset by this, consult with a reputable genetic genealogist. I recommend my affiliate, Legacy Tree Genealogists. I will also email you privately. I am willing to take a quick look at why he thinks this, if he writes it up in detail.

  108. from the match
    “My dad and you share 270cM over 13 segments. Ancestry shows the likely relationship between you as follows: Martha Tiger-Ochs and William Ballentine share 270 cM. 

    This table from Ancestry shows the percentage of the time people sharing 270 cM have the following relationships:

    62% 2nd cousin, 1st cousin 2x removed, Half 1st cousin 1x removed,, Half 2nd great-aunt/uncle, Half 2nd great-niece/nephew

    32% 1st cousin 1x removed, Half 1st cousin, 2nd great-grandparent, 2nd great-grandchild, 2nd great aunt/uncle, 2nd great-niece/nephew, Half great-aunt/uncle, Half grand-niece/nephew

    5% 2nd cousin 1x removed, Half 2nd cousin, 1st cousin 3x removed, Half 1st cousin 2x removed

    <1% 3rd cousin, 2nd cousin 2x removed, Half 2nd cousin 1x removed, Half 1st cousin 3x removed

    The point is that DNA shows you and he are more closely related than what both of our well researched records show. That typically means there is what is known as an NPE (non-paternity event or not parent expected) somewhere back in time that the historical records will not show.  Now obviously we do not know exactly what that is. I put all the DNA data we have into the What are the Odds online tool to try to see if we could eliminate some of the above possible cousin relationships between you and my Dad. All but 2nd cousins or half 2nd cousins were eliminated due to the amount of DNA you two also share with your many shared matches. 

    So it is highly likely you and he are 2c or half 2c.  I am not saying that any one scenario is correct (we do not know!) but we need to understand that the DNA says something else is going and we need to be open to what that might be!”

    • Your match has stated it well. One more thing I would recommend is that both of you use clustering to check if you have matches on ALL your great grandparent lines. See
      The most likely explanation is that one of your great grandfathers is not the person of record. These things do happen. Try and get a 2nd cousin from each great grandparent line to test and see if they all match you.
      For those who do not want to use a public company, I recommend testing at 23andme but not opting into the relative comparison. Then upload to as a “research” kit so no one can see it in their results. That means that just the people who know the kit number, like your family, can compare to those DNA results.

  109. I have a new close family hit. His name is Otha (Sonny) Wright. I only have 3 close family, my half brother, my half sister and the new male match. Do you think he is my half sibling? He was born in 1960 and I was born in 1961. I wish I knew how to do this, I’m not sure what to do next or how to figure out if he is my half brother and if his father is my birth father. My half brother: Shared DNA: 1,671 cM across 67 segments. My half sister:Shared DNA: 1,668 cM across 79 segments. New match (?) Shared DNA: 1,306 cM across 55 segments. Is he my half brother? Would his father be my father? Thanks so much, I am so confused…need help please. Thank you.

  110. Hi Kitty!

    I’ve read so many of the posts and your replies to get some sort of clarity but I think this may be a little more complicated.

    I am helping my father in law with his results as he was adopted and we’d heard that his parents from Ireland were related. His closest match on AncestryDNA was a man with 1195cm across 46 segments. We got in touch with his son who is helping his father as well and found out his father was adopted too.
    I ran the raw data through GEDmatch 1×1 for my FIL and his closest match:

    Largest segment = 84 cM
    Total HIR = 1219.7 cM (34.09 Pct)
    Estimated number of generations to MRCA = 1.8
    42 shares segments
    523360 SNP’s used for comparison
    57.689 Pct SNP’s are full identical

    The numbers don’t seem to fit together when I compare them to most charts.

    I also ran his closest match through AYPR and it came back negative.

    This man is dang near identical to my FIL but is 15 years older. Any ideas?

    Thank you so much for helping everyone by the way! This stuff can be incredibly confusing!

  111. I have spent several years dna tested and looking for a biological father (my mother told me on her deathbed my ‘father’ was not by biological father) but was an unnamed man she had a very brief affair with).
    It now appears that I have a match of 1718 cM’s, which just showed up on a different dna site than Ancestry to which I had uploaded my results!!
    So far this match (a male) has not replied to any emails though… 🙁
    I am waiting for a response, hopefully someday soon, as I am in my mid-sixties and he is in his 70’s in Scandanavia.

    • HM, how exciting. Probably a half brother or an uncle. Sometimes people have changed emails so …
      If he has a tree, try to figure it out from there. Do you match relatives on his mother’s side? Then an uncle.
      Otherwise you have to build a tree for him yourself. GENI has many Scandinavians, search for his name there. Also google, Facebook, etc … Good luck!

  112. Now that Ancestry has Rolled out the Ancestry Health Plus it was the Final Step that me and my Brother have taken for the maximum precision and accuracy of DNA Testing.Previously the same as it was at Family Tree FTDNA our shared Centimorgans were 2,390 within 61 Segments.Now Ancestry is saying that it’s only 2,386 Centimorgans within 64 Segments.Now that the amount of Shared Centimorgans have been reduced slightly,and the Segment count has been increased slightly on Ancestry would that make us 3 Quarter Siblings instead of Full Siblings?I ask because our Father is unable to hold intelligent Conversations and our mother is a compulsive Liar that likes to sleep with any man that she can get between her legs.

  113. Hi Kitty,
    I’m not doing a very good job of explaining the hypothesis. Sorry. My half sister and half brother (same mother, all different fathers): Ancestry DNA= My half brother is 1680 CMS across 51 segments, my half sister is 1350 CMS across 39 segments. Half brother shares 1624 CMS across 48 segments with our half sister. More family matches as well as quite a bit of paperwork confirms our relationship through our mother.

    We all have a match that is about two generations younger. That person is matched to many shared matches of ours on our mother’s side of the family.
    That person shares 477 CMS across 19 segments with me, 320 CMS across 14 segments with half brother, and 981 CMS across 32 segments with half sister. In addition, they share matches on our half sister’s father’s side of the family.

    Our theory is this person is a grandchild of one of our half sister’s full siblings, so a full grand nephew/niece to our half sister, and half grand nephew/niece to both my half brother and I. The Shared Centimorgans seem to work according to the dna Painter Chart. Unfortunately we do not have any contact with this person, so uploading to Gedmatch is not a possibility.

    Thanks for your insight,

  114. This blog was so informative. I have also filled out your data form.

    I have a close connection I have no idea of. We have only identified that the family hails from an area close to that where my mother’s family is from. My mother does not know her real father so I am desperate to understand these results better.

    Shared DNA – 3.1% (219.2cm)
    Shared segments 5
    Largest segment 80cm
    2nd largest segment: 51.4
    3rd largest: 48.5
    4th largest: 28.3
    5th largest: 11.1

    Any interpretive advice welcomed.

  115. Hi Kitty
    I’ve recently had a DNA test result through Ancestry & I’m led to believe that my father may not be whom I thought .
    I have hundreds of DNA matches , my closest to be 249cm across 12 Segments , Ancestry advise maybe a 2nd or 3rd cousin ?
    I have no idea how this Cm & segment stuff works even after reading your blog.
    I’m wondering if you could kindly give advice on how to perhaps go about finding out who my Paternal Father maybe .
    Kind regards

  116. Hello Kitty,

    I hope you will respond to this. I have never met my paternal grandfather, nor have I confirmed who he is. I did both 23 and me and Ancestry, and I have come up with some theories, but let me run them by you.

    I found relatives on my mother’s father and mother’s side. Now as for my father, I know he was adopted by the man my grandmother was married to. I found several relatives. One is 603 cm, another is 438, and another is 408 cm. All female, and all from the same family name. The highest percentage is related to my suspected great uncle. The lower two were daughters of my suspected great aunt. Does it sound right?
    Also, 23 and me matched me to a female from the same family at 10.03% match, or 750 cm. I believe she could be my half aunt. She is the aunt of the other three matches. Does this all sound right? I am trying to differentiate between my grandmother and grandfather’s side of my father. Please help.

  117. So if she is the aunt of your other 3 matches then she is your great-aunt, the sister to your unknown grandad. The other 3 matches would be all first cousins once removed to you.

    This calculator is helpful and has a chart which makes it easier to see the relationships:

    So build their tree. Does she have a brother who is your likely grandad? Have you gotten in touch with any of them?

    I removed your email address from your comment but will reply privately as well

  118. Need some real guidance and understanding, because I can’t see the forest for the trees!

    Closest match ….. same person:

    Shared DNA 84.3‎ cM
    Shared segments 1
    Largest segment 84.3‎ cM

    Shared DNA: 78 cM across 1 segments
    Unweighted shared DNA: 85 cM
    Longest segment: 85 cM

    Shared DNA
    1 segment

    What does this mean? I’ve never seen a larger segment match with just one segment.

    Thank you for any insight and thank you for your invaluable blog.

    • Hi Missy,
      Sorry for the delayed response. Single segment matches, even large ones, can be from a very long ago ancestor and so are less worth following up on than a match with multiple segments.
      As to the slight difference in sizes between companies that is normal and not significant. The SNPs tested vary between companies so the start and end points can vary slightly.

  119. I have been trying to find who my paternal grandfather is I had a dna test on ancestry one of my matches shares 127 cm 2 percent shared acroaa 8 segments longest segment 29 cm I thought this match before she had her dna tested may have shared a grandfather with me but now it’s seems a bit low do you think it’s possible

    • Yes it is possible but twice as likely to be an aunt/uncle/niece/nephew according to the calculator at

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