> If there is ever a future time you can be punished for your DNA, the only people who can possibly be 'grandfathered' in are the ones who've avoided submitting their DNA in the first place.

I don't support the point of view of the GP but in all fairness, if we come to the society where DNA is used for widespread discrimination, it will probably be semi-voluntarily collected from the majority of the citizens anyway (e.g. want to have a driver's license? submit the DNA)