Alright...can't help myself so here goes...govt collection of DNA can only have two possible uses IMHO:
1.) To identify future criminals
2.) To predict your future health concerns and thereby make some determination of insurability. I know it sounds Orwellian, but if you haven't read the book 1984 in a while pick it up and give it a read and then think about what's going on these days. Obamacare has rationing councils in place already. When the law is fully implemented they will have the ultimate authority on how, when and what medical care is available to you. Is it really that far fetched to think that they want some assurance that their investment (your medical care) isn't going to get cancer and die in the next six months?
Just a thought