The act of checking your own DNA seems innocent enough: you swab the inside of your cheek with a Q-tip and send it to a company in the hope of learning more about your ancestry or your predisposition toward certain diseases. But those companies could also be sharing your personal DNA data with law enforcement, even if you’re not suspected of involvement in a crime, and even if the company’s terms don’t bother to warn you.

FamilyTree DNA recently apologized for not telling customers about their agreement with the Federal Bureau of Investigation (FBI) to grant the agency access to customer data. In an email to its customers, FamilyTree president Bennett Greenspan said the company has “processed a handful of cold cases for the FBI.” FamilyTree does have a privacy function that customers can opt to turn on that prevents DNA matching, but the default setting doesn’t prevent matching. Additionally, when one switches it on, it makes it impossible for folks to find distant relatives. So one of the main purposes for using such a service is really defeated if one wishes to preserve one’s privacy.

The type of DNA matching law enforcement uses when they’re searching these databases isn’t foolproof, and can often implicate the wrong person in a crime. For example, in 2012, paramedics accidentally brought the DNA of a homeless man they were treating to the scene of a murder they later responded to. This led them to arrest Lukis Anderson, who spent five months behind bars before his name was finally cleared. As the Electronic Frontier Foundation’s Jennifer Lynch put it, “allowing police and private companies to use these techniques without legal constraints violates privacy and could link people to crimes they didn’t commit.”

But the fact that police are using and abusing such databases shouldn’t surprise anyone. The federal government has become more and more fixated on collecting the intimate biometric data of millions of innocent Americans, and companies routinely bend over backward to appease the feds.

For example, Amazon has been selling its facial recognition tool, known as Rekognition, to law enforcement agencies all over the country, and has actively pushed Immigration and Customs Enforcement (ICE) to purchase the tool as well. Many local law enforcement agencies have praised Amazon for their partnership. Rekognition has the ability to recognize the faces of “tens of millions” of people. But the tool has many flaws: it even misidentified 28 members of Congress as suspected criminals.

The Department of Homeland Security (DHS) has been working on a biometric database of 500 million people called the Homeland Advance Recognition Technology (HART). Among other biometric indicators, this massive vault would hold DNA, facial, and voice recognition data on millions of people. And law enforcement agencies are notorious for sharing data with one another, so it’s easy to see how anything collected from DNA companies by the FBI could be lumped into the HART database too.

When federal agencies are this overzealous in their push to know everything about us, it becomes crucial that the private companies holding our data apply due process rigidly and don’t blindly turn over data to the government without probable cause.

Thankfully, there are a few major companies willing to stand up to federal demands and protect your privacy. Both Ancestry.com and 23andMe claim that they require a court-issued warrant before they’ll turn over any of your biometric data to law enforcement. 23andMe has received five requests for genetic data thus far, and has denied all of them. That said, because genetic data isn’t protected by HIPAA and other privacy regulations, we’re left to simply trust that companies will follow their own privacy policies and stand up to encroaching law enforcement agencies.

It’s simple: if you’re truly concerned with protecting your genetic data from the prying eye of the government, the only solution is to not share such data with third parties—even if you believe they’ll handle it with care.

Dan King is a senior contributor at Young Voices, where he covers civil liberties and criminal justice reform. His work has appeared at The American Conservative, Reason, The Week, and The Weekly Standard.