But when you ship off your saliva, law enforcement could have access to your DNA.
Police could use genetic information it gets from those companies to identify you in a criminal investigation, even if you've never used one of those services.
Jacksonville resident Eric Yarham wanted to learn more about his family tree, so he mailed off his saliva to 23andMe.
"Just trying to unravel the mystery that is your genetics," said Yarham, who lives in the Riverside area. "That lingering 0.3 percent is sub-Saharan African. So that's swimming around in my DNA." Yarham had no idea police could request his genetic information.
Both 23andMe and Ancestry confirm your genetic information could be disclosed to law enforcement if they have a warrant.
Action News Jax asked 23andMe Privacy Officer Kate Black whether the company notifies customers about that possibility before they mail in their DNA. "We try to make information available on the website in various forms, so through Frequently Asked Questions, through information in our privacy center," Black said.