A couple days ago I warned about a study about "post partum depression" that collected your DNA (but claimed your name would be kept private by the researchers).
Well, now (AP LINK) I read the USGov't is pressuring genetic databases to get your DNA. These are data bases that find your ancestral background, not medical ones.
And the gov't already has a database of millions of folks who got DNA taken when arrested or were in the armed forces etc.
most of the cases cited in the article were released by court order, but you can see the potential for abuse...