20 million people (a figure for the US I imagine) have uploaded their genetic profiles to consumer DNA sites like Ancestry.com, 23andMe, and GEDmatch. The first two have pledged to keep their users’ genetic information private and the third severely restricted access. But a warrant granted in Florida might supersede their good intentions.

Last week, however, a Florida detective announced at a police convention that he had obtained a warrant to penetrate GEDmatch and search its full database of nearly one million users. Legal experts said that this appeared to be the first time a judge had approved such a warrant, and that the development could have profound implications for genetic privacy.

Other agencies are sure to try to get similar warrants, so lets not forget that at the scale these services have reached, there are now implications for everyone, not just those who sent their DNA for analysis.

If that comes to pass, the Florida judge’s decision will affect not only the users of these sites but huge swaths of the population, including those who have never taken a DNA test. That’s because this emerging forensic technique makes it possible to identify a DNA profile even through distant family relationships.

In 2018, California police used GEDmatch data to identify a man they believe is the Golden State Killer, Joseph James DeAngelo. Since then, other police forces have followed suit, turning tools meant to find relatives, into ones that can be used to search family trees for criminals.