The government
Depending on what countries you’ve lived in, the government may have your DNA on file. In the UK, the police and the government have extremely broad, poorly defined powers to collect DNA samples. The UK, with a population only about one-fifth the size of the United States, maintains a DNA database just as big as the one in the United States.
In the United States, police don’t need a warrant to collect your DNA from a public place, like a used coffee cup at a cafe or a half-eaten hot dog at a ballpark. Logging every empty beer can on a frat house lawn for later DNA profiling is highly impractical, so the FBI and several states’ police forces have begun taking DNA profiles in every arrest they make. If you’ve been booked, whether you were charged or not, the government might have your DNA.