Ideally parents would teach their kids what they need to know and the school's hands would be washed of this issue. But, most parents seem to suck these days, I cant ever see that happening.
Because of idiots with kids, unfortunately schools have to tackle the problem. To teach abstinence only in unacceptable and dangerous. I cant imagine most kids don't know about condoms and STD's, though. I remember knowing about AIDS, STD's, condoms and pregnancy by the second grade and I couldn't wait till the day I'd be able to use one (condoms that is)