If you’ve ever succumbed to the temptation to have your DNA sequenced by a genealogy company you probably learned some pretty interesting things about your heritage. You might have discovered that parts of you come from places you never expected, or that your recent ancestors are something of an offshoot on your larger family tree.

Whatever the reasons for your decision, you handed over your DNA to a company, and if you chose to make that genetic information public in a searchable database you’re contributing to a DNA privacy crisis that is just beginning to take shape.

In a new study published in Science, researchers led by Yaniv Erlich of Columbia University took on the seemingly incredible task of attempting to identify an individual based just on their DNA and a few seemingly mundane details about their life.

“Using genomic data of 1.28 million individuals tested with consumer genomics, we investigated the power of this technique,” the researchers write. “We project that about 60% of the searches for individuals of European-descent will result in a third cousin or closer match, which can allow their identification using demographic identifiers.”

The meteoric rise of DNA testing for entertainment purposes and family history searches has resulted in over a million genetic sequences being available via public searches. Companies like GEDmatch let you compare your genome with countless others in search of relatives, and with a little guesswork it’s fairly easy to triangulate the position of an individual on a family tree.

To prove this point, the researchers started with DNA information and a couple of basic details about an individual and, after finding a couple of their relatives via genetic archiving services they were able to determine who the person was without so much as a phone call.

A similar cross-referencing technique was recently used to break the long-cold case of the Golden State Killer after a relative’s DNA popped up on a genetic testing site. That was obviously a positive outcome in the search for the culprit, but the fact that a person can be identified by their DNA even if they themselves have never made it available to a genetic testing company is somewhat spooky.

Ultimately, the researchers found that over half of U.S. citizens have at least a third cousin match in DNA databases, and roughly 15 percent have even closer relatives to link to. Those numbers are growing every day, and it might not be long before just about anyone can be identified thanks to their relatives’ genetic markers.