Have you gotten your genetic information back yet? 23&Me, Ancestry and a dozen other places will offer you multiple reports on your genetic ancestry and your potential for certain genetic illnesses and all you have to do is send a swab back with a bit of your DNA for them to analyze. Ah, but what happens after all that? When the Golden State Killer was caught it was through California law enforcement matching "public DNA databases." But imagine if someone had tampered with those records, a person could just as easily be framed in this manner.
Once you've given up your genetic material you are signing away certain rights to it. For instance, they will likely use the DNA as part of their database in certain research. So much more potentially could be done with DNA at this point and as technology progresses, the potential is mindboggling. That said, DNA doesn't have to be signed over to be used for nefarious purposes. If you have hair that sheds that is one way you could mistakenly offer up your DNA. A flake of skin, an eyelash, saliva left on a straw in a restaurant, so many ways you could have your genome "snatched."
In the era of Big Data, all information is a commodity. As a result, companies like 23&Me aren't primarily making their money by selling the results of their genetic tests. They make quite a bit more from selling anonymized genomic data. That said, it's no difficult feat to identify the individual after the fact from the anonymized data. Facebook, for instance, was working with several hospitals before Cambridge Analytica and were interested in a "data sharing agreement." The anonymized health data likely could be eventually matched with the users (for what purposes, God, the hospitals in question and Zuckerberg only knows).
Then there's the fact that insurance companies and employers might be interested in getting their hands on your genetic profile. This, of course, is the reason for the Genetic Information Nondiscrimination Act which became federal law in 2008. In theory, it prevents insurance companies and employers from making people take a genetic test but wouldn't necessarily keep employers and insurance companies from finding that information on their own if it was available in some public or private database.
Then there's the fact that genome companies can be hacked. Even highly regulated industries like banks and credit services like Experian have had major data breaches, but genetic information is not nearly so tightly locked away. Imagine if the Ra-elians (a French alien cult who have been interested in cloning since the 1990s) or some other group hacked the service you used. It's possible there may already be an inter-special hybrid bearing your genes on an unnamed, unmarked island somewhere.