I agree that forcing birth control on kids is a bad idea. They won't understand why it's so important, and instead do everything they can to resist taking it. Teenagers are weird creatures. Some believe they're invincible, and will therefore never contract any illness that will stick around for the rest of their lives. Or, disturbingly enough, there are more and more teenage girls who WANT to get pregnant, because they crave the unconditional love that a baby would provide.
Educating kids is one thing, but I think it's also important for the parents not to have just the one talk, but to keep an on-going, open dialogue with their kids about sex, pregnancy, and illness. I know it's different all over, but my school didn't offer the sex education bit until...11th grade. Most of my friends were sexually active long before then. I actually learned more about HIV the year before, in biology class. (We had what they called sex ed in 4th, 5th, and 6th grades, but those were more "You're about to hit puberty. This is what a period is. This is how you use a pad.") Parents can't rely on the school system to take care of the edication side of things. It's usually just a lecture given to the whole class, and a lot of kids are too nervous to ask certain questions in front of their friends. Or questions pop up after the lecture. In that same vein, parents need to stay up-to-date on research and techniques, or at the very least be willing to help their kids find the answers they need.