How a Third Cousin Could Give Away Your DNA Secrets

Relatively simple tests that can analyze an individual’s DNA have proved a boon in the fields of medicine and criminal justice, not to mention genealogy. They can identify genetic disorders, implicate or clear criminal suspects, and help people fill in their family trees. In recent years, however, it’s become clear that DNA data can be used in ways we never expected or desired. As a result, more people have begun to worry about what might happen to their most intimate personal information.

It’s difficult enough to know how your DNA data might be used now, let alone in the future. And unlike a bank account number or a password that can be changed, once it’s out there, it’s out there for good. There are obvious reasons for companies such as insurance providers to take an interest in your physical makeup. The U.S. military in 2020 advised its personnel against using consumer tests, in part because a result showing a marker for disease could both be inaccurate and stymie a career. Your genetic data could reveal information you might not want public, such as an unacknowledged parental connection. If you’re a lawbreaker, or so much as distantly related to one, there’s the fact that law enforcement agencies increasingly rely on DNA data to solve difficult cases. Also, the tests can reveal a person’s ethnicity, which can be dangerous in some contexts.