At one time I taught sex education to 5th graders. Boys in one class, girls in another. I thought, the parents thought, the district thought that was a good age. We didn't discuss birth control. My husband taught high school and taught sex ed. The curriculum covered birth control methods as well as abstinence.
When my son was about that age he and I looked at a few good movies about "bodies" and read, together, some books. Later, when he fell in love in high school I didn't treat it as "puppy love." We sat together and talked about everything: IF he should decide that he loved this young lady enough to make the commitment to her and become intimate how SHE would feel. (She'd start writing Mrs. XXX XXX on her notebooks, she'd be thinking about wedding gowns, she'd be picking names for her future children, etc.) I told him girls react differently to intimacy - at least I did. I told him that IF he and she decided to be intimate he needed to use protection because... one sentence we would never, never hear in our house was... Ma, XXX is pregnant. I told him I would buy condoms if he made that choice so he wouldn't have to face a pharmacist. We talked about how teen pregnancy forever changes your options. How teen moms are more likely to not finish their educational plans and are likely to have a second baby within two years of the first. We talked about teen parents and poverty. We talked about respect for him. Respect for her. We talked about "urges" and "needs". I told him I would like for them to wait but I couldn't follow them around and in the end I couldn't make their decision. It was a look-me-straight-in-the-eye conversation. It was a conversation which we repeated frequently. There was no yelling, no embarrassment, no scolding, nothing "out of bounds."
Schools can only do so much. I don't think an "abstinence only" curriculum is best for teenagers. We delay adulthood for a long time in this country. I think we need to take a deep breath and have a real conversation with each of our children - starting early and repeating it often. I think we need to understand the difference between what we wish would happen and what is likely to happen. As adults we know that teen love isn't the same as mature love, but they don't.