The guy I was screwing around with was 32. He knew what he was doing, but even if he hadn't I did. I didn't want any diseases or babies with my Dad around, so I was smart enough to go to the free clinic and get on the pill as soon as sex was on the brain.
But should we punish the kids for being naturally exploratory? No. Instead we talk to them about the responsibilities and what comes with having sex. That way they can make smart choices. I didn't have my parents to talk to about it, but my grandmother, knowing she wasn't going to be around forever, told me and my brother about sex at the age of ten. Because my parents weren't going to be the ones to do it.
Treating it like it's some... I don't know, horrible awful thing that should never ever happen, educate the kids.