A judge said police can search the DNA of 1 million Americans without their consent. What’s next?

For the first time, a state judge has forced a public genealogy site, GEDmatch, to allow police to search its entire database of DNA profiles. A detective wanted to find distant relatives of a serial rapist in hopes that their family trees could help him home in on a suspect—even though most of the 1.3 million people who have shared their DNA data with the site haven’t agreed to such a search.

The search warrant, reported this week by The New York Times, raises the alarming possibility of similar police searches of giant direct-to-consumer DNA sites such as Ancestry.com and 23andMe that are now closed to everyone except company customers who willingly submit a saliva sample.

Since police tracked down the suspected Golden State Killer in April 2018 by uploading crime-scene DNA to GEDmatch, forensic genealogy has led to arrests in scores of cold criminal cases. But privacy concerns have arisen because users didn’t know their DNA data were being searched, and because relatives who never took a DNA test could come under suspicion. In May, GEDmatch restricted police searches to participants who had given consent, cutting the number of available DNA profiles to 185,000. Then in September, the U.S. Department of Justice (DOJ) eased some concerns by issuing a policy that limits searches by federal law enforcement agencies to violent crimes and DNA profiles with user consent.

Read more at sciencemag.org.