Speaking of ages, I've brought this up before and I'll keep bringing it up.
If you are old enough to serve, you are old enough to vote and you should also be old enough to buy tobacco and alcohol. Granted, those are probably two of the worst, most deadly things out there, but its not fair.
There should be one age for all of this. 18? 19? 20? I don't care, just pick an age.
This would also work in reverse. You'd have to be 18 (or x) to get a sex change, and other things minors are allowed to do. Fuck 17. Fuck 21. Pick and age inbetween. Does that make sense or will States Rights mess with my concept?