As others have already answered, you share DNA with relatives. Anonymisation is certainly good, but I wonder how well it works with something so inherently personal.

Some areas are conserved quite well, so you can find inferre the degree of kinship quite well. Another aspect is that imo one of the dystopian uses of DNA is for health insurance. And for that you wouldn’t necessarily need to know whether someone has a certain gene or not. It would probably be good enough to work with probabilities, if you know someone else in the family has a certain gene.

But I am probably pessimistic here, because of course there is tremendous value for research here.