The problem is, according to a major 2017 study from Vanderbilt University of 90 DNA testing companies, 39 percent of them had no written policy online about how they use genetic data. We looked at four of the biggest companies — 23andMe, Ancestry, MyHeritage and FamilyTreeDNA — to see what they really do with your identity.
…[Y]ou should be aware of three major groups that DNA-testing companies may share data with: research institutions, private corporations and law enforcement.
The safest thing you can do after taking a company’s test is delete your data and get your DNA sample destroyed.
Your DNA info can be removed from the testing company’s servers, but it can’t be recalled from the third-party corporations or universities who may already have it. In general, the less diffused your data is, the less likely it will escape into the wrong hands.
Read full, original post: How secure is DNA testing?