Well, since you opened it up Nick, I will share a few thoughts.
There are a couple of misconceptions about sex when one is young that need to be cleared up. One misconception has grown over the time since I was in high school to now and that is the idea that "kids are going to do it anyway".
This is said as if there is some overwhelming biological urge for kids to have sex by the time they are teens. Are there biological urges? Of course there are. Are they overwhelming? No. There hasn't been some kind of huge evolutionary leap in teens in the past 50 years when most kids did not have sex to today when most kids do. Teens are biologically just as capable of remaining abstinent now as they were when grandma was younger. The difference is adults are not maintaining the expectation that the kids will not engage in sexual activity. Since most adults are saying things like "Well, we know that you'll probably do it even though we don't want you to, so make sure you protect yourself." We all are intelligent enough to know that this is a tacit permission to go on ahead with sex. This implied permission combined with the fact that there is so much peer pressure for teens to have sex, makes it very likely that they certainly will.
And I have to say that it was my generation that capitulated on the sex issue. I went to school in the 1970's. Ten years prior to that we had had the great societal revolution of the late 1960. What had happened in that 10 years was that the generation just ahead of us were still selling the idea of "free love" and "make love, not war" and "sex, drugs and rock n roll" even while parents were dealing with the upheavals in society, were totally confused and not giving a lot of clear direction. So, kids I went to high school with were having sex, but were feeling pretty guilty about it. I always remained abstinent, but boy do I remember waiting in fear and anxiety with several of my girlfriends for her to have her period so that she would know she wasn't pregnant.
This brings me to the other misconception about sex: That it's just about sex. That it's just about having fun and doing something that feels really good.
It's not. And it never has been.
Before the Summer of Love (1967, ancient history I know) kids by and large didn't have sex because everyone in society expected that one would wait until marriage and if one didn't one's reputation truly suffered. There was some sexist hypocrisy going on as boys were apt to be more sexually active than girls in the generations prior to the late 60's, but if a girl had sex outside of marriage, her reputation, not only among adults but among her peers truly suffered. But most kids, boys and girls both, waited until marriage.
The thing was, being abstinent because of society pressure didn't teach the real reason why one should remain abstinent. Therefore, when society pressure was lifted, then everyone had the idea of "if it feels good, do it".
Now we've had 40 years to understand why just feeling good isn't enough. We can see that there is a lot more to sex than just the act. And I'm not talking about just diseases or teen pregnancies, although these are major concerns.
Sex is far more than just an act that "feels good". Sex is a way for two humans to connect on a most intimate level. The King James Version of the Bibles word for sex is "to know". That is a pretty good word, because it equates sex with an intimacy so great that two people can be together in true knowledge of each other. When two people create this kind of intimacy with each other, via making love (as opposed to just having sex), their bonds to each other become a firm foundation for a lifetime together.
Take that intimacy out of sex, make sex just be about the act, the ability to truly "know" a partner becomes diminished.
It is not coincidence that the rise in pre-marital sexual activity among teens and young adult has occurred right along with the astronomical rise in divorce rates. By reducing sex to a fun but relatively unimportant part of life, humans are losing their ability to truly connect emotionally and mentally with one another. When teens make sex an important part of transient relationships (because be honest, most, not all, but most teen relationships are not going to last) they lose the foundation of what builds a truly lasting relationship with another. By joining together with several partners, then leaving and moving on to yet another partner, the idea of leaving a relationship becomes easier and easier and hence divorce is now rampant. And, with divorce comes the problem of kids having to visit their parents rather than truly live with them, which causes disruption in their developing the most basic foundational relationship and because they lack a strong parental relationship, they are far more likely to fill the gap with...you guessed it...sexual relationships and the whole thing spirals out of control.
The main reason why high school kids should (and can) wait until marriage before having sex is that it will strengthen your ability to have a firm lasting marriage, intimately connected with a life partner, rather than spinning through life, leaving one relationship after another and leaving an ever widening wake of people whose capacity to intimately connect is more and more diminished.