This article in the Washington Post states that more and more states are rejecting federal funding for sex education in the schools, since the funding is tied to having an abstinence-only program taught to students. Any reasonable person will tell you that simply telling people, especially teens, to not have sex just doesn't work.
Besides, IMO, it isn't the job of the federal government or the schools to teach kids about sex. That responsibility rests solely in the hands of the parents, and it belongs in the home. Just like it isn't the job of the government to have programs like DARE. Can't parents simply tell their kids that drugs will fuck up your life?