Many of my matches at ancestry.com are afraid to upload their raw data to GEDmatch because of their fears about DNA privacy. Here is what I want to say to all of them.
These personal genome tests are not your full genome, just a sampling of the places you are likely to be different from the next person. Remember that we all share 98-99% of our DNA with every other human being.
There is not enough information in these tests for some future mad scientist to make a clone of you.
The GINA law protects you from insurance companies or employers using your DNA information to discriminate against you or deny you health coverage.
So are you afraid that someone will know your blood type or eye color? What about unusual medical conditions? They can only figure something out about you if they know the kit number of someone with your same traits. All they get to see is where the DNA overlaps with another kit, not the raw data itself. And they would need far more knowledge about DNA than the average tester has, to use those overlaps to figure out anything about you.
A prominent genetic genealogist with a PhD in biology, Blaine Bettinger, has so little fear about people seeing his DNA data that he posted it all online for anyone to download and look at!
Your identity cannot be stolen from this data sampling of your DNA. It is like a giant fingerprint not a credit card number.
On the other hand, if you have any criminals in your family it is just barely possible that your DNA could help track them down. Not a good idea to do DNA testing if you are a criminal yourself, although the FBI uses different markers than what these tests look at.