[HenryBemis]

Well they can narrow it down to the family, unless it was the very DNA giver that left that DNA sample on the scene of the crime.

And since 23andme (as I assume others) don't do these anonymously, there is no hope. Unless people use someone as a proxy (i.e. I-1 give my sample to a male colleague to send it as his-2, he-2 gives his sample to someone else to send it as his-3, and so on..). Police would eventually find the guilty in case of a crime, but the 23andme's of this world will be selling confusing (wrong) data.

[stef25]

There are plenty of cases where DNA is found at the crime scene, run through a database, match is found with a relative. Then the cops start looking at the family and boom there's your shady uncle with priors they got their guy.

[quickthrower2]

Yes it has come up a few times on forensic files usually on cold cases.

[dylan604]

If this was someone trying to fly under the radar by using this scheme to buy burner phones or some such, sure. But this is literal DNA, so even in your attempts to obfuscate, they’d know the name and the sample do not line up, but then be able to link the sample to a family and then figure out who you really are

[pavel_lishin]

They can narrow it down to individual family members, based on how much DNA overlap there is.