The purpose of sex education is get the kids hyped up to want sex.
Newsflash,larson: Teenagers want sex. They have just entered puberty and their bodies are telling them that it would be a very good idea to start reproducing NOW, for fear that the species will die out. No matter how hard you tell them not to have sex, their bodies are winning the argument. It has nothing to do with religion. It has nothing to do with secularism. It has nothing to do with abstinence, and has nothing to do with safe sex. It's all about biology at this point.
Don't get me wrong, I'm not saying that every teenager everywhere is going to jump in the sack the moment they hit puberty, but the desire is there. All of your prohibitions are warring against millions of years of evolution. Even for those of us who didn't have sex in high school, we wanted to.
Wouldn't it make a lot more sense, from a mature, rational, adult standpoint, to ensure that if teenagers are going to have sex with or without our permission, that we give them the tools to prevent STDs and pregnancy?
Or does it actually make sense to you to tell your teenagers "no" and pray really, really, really hard that they'll listen? It didn't work too well for Sarah Palin, what makes you think it'll work for you?