Add me to the list of the folks whose parents taught them the basics of sex: where babies come from, how they get there, etc. I think, in the ideal society, it should be the parents who do sex education...they (should) know their kids, they know what they respond best to. However, since we don't live anywhere near an ideal society, its up to the schools to provide comprehensive sex education including relationships, sex, reproduction, contraception, protection, (in the later grades) abortion, STDs, and yes, abstinence.
I think I'll quote Joycelyn Elders (Surgeon General under Clinton, was fired for basically saying we should tell kids that its okay to masturbate) here: "I'm against abstinence programs because I really consider "abstinence only" child abuse."