I see you were on the same thread I got pinged to - the one about the 14 year old girl dying from her birth control - definitely parental responsibility!!
Yes. Since I have a 14-year-old daughter, I know from experience that it's not impossible to keep them from having sex. In the first place, if they've got any sense, they don't want to. And on the other hand, you just have to be around them all the time. "No girl ever got pregnant in front of the chaperone," as a wise man said.
I'd get chewed to bits if I said this on the other thread (and I'm planning to go to bed soon, anyway), but I think some of the posters have an ulterior motive: They want unmarried girls available for easy sex, and they don't want the inconvenience of condoms, so of course they're in favor of free access to hormonal contraceptives for women. "What's a few blood-clot or STD deaths, as long as we get to do our business?"
Wow, did I say that? I must be getting to the Really, REALLY Cranky stage of pregnancy :-).