“Genetic data is immutable and can reveal very personal details about you and your family members,” the Electronic Frontier Foundation cautioned in a blog post about 23andMe’s potential sale last year. If your relatives have used 23andMe in the past, your data is also at risk.

Because some DNA is passed on from parent to child, there’s a strong correlation between the genetic material of people within the same family. If anyone in your family has provided a genetic sample to 23andMe (or another DNA test kit maker), the company already knows something about you—even if you’ve never personally given them your data. If you know that a relative has used 23andMe, consider reaching out to ask them to delete their data.

The privacy concerns of giving a company your genetic information are not theoretical and are not exclusive to 23andMe. Law enforcement officers have used genetic profiles from home DNA kit companies in the past. In a 2018 case, law enforcement used a combination of genetic profiles from GEDmatch along with carefully constructed family trees to identify a murderer after 40 years.

Both Wirecutter and the EFF noted that 23andMe does not voluntarily share data with law enforcement and requires a warrant before providing any data on its customers.

Many of 23andMe’s customers have used the service to discover long-lost relatives or piece together family history that might have otherwise remained unknown. It’s unfortunate that the company’s data security practices and now uncertain future may undermine those discoveries.

This article was edited by Caitlin McGarry and Erica Ogg.