If sex is to reproduce, why are you having sex out of the fertile period then?
No offense, but it sounds a little bit paradoxical don't you think?
So, sex before marriage? Absolutely! You learn so much about someone when you have sex, that I really think it's actually a good thing to know if you're compatible before getting married... I've heard of so many couples who broke up because things were not working in bed... That and I can't imagine getting married to someone I don't know all I can about. Not to give too much information, but what if the guy doesn't care to please anyone but himself? What if he's a perv? You won't be able to know until you try, and it would suck to find out after being married... It just says so much about the person... IMO. Not that I find marriage to be such a big deal anymore, but divorces suck.
That, and, well, usually the first time sucks, and I would find it a real downer on a honeymoon personally.
More seriously, I think it should be everyone's choice... It doesn't shock me if a 15 year old has sex, as long as she's 100% sure it's what she wants, and not just to please her boyfriend, and that she's reasonable about it.
Honestly, I just don't think that sex is such a big deal, as long as it's done responsibly. I don't think it's degrading, and I do find it sexist to say it is for girls, but that it's never mentionned for guys. It's something natural, and girls have hormons, too.
And no, I didn't have sex at 15 - I was 19, with what I thought was the right guy at the time, although I admit I was mostly curious about what all the fuss was about, too.