In what way does sex at 16 immediately jump into moral issues exactly?

I don't buy for a second that being sexually active as a teenager somehow equates to lack of moral fortitude.

There's plenty of teenagers that are aware of birth control and use it appropriately. Do they lack moral fortitude, too?

Having a kid at 16 will screw you up. Most people have a moral objection to screwing up their life like that, as well as the practical objection. Most religions of the world have some form of moral objection to sex outside of marriage, it can be easily argued that the moral objection comes form the practical issues. (most religions predates any form of effective birth control. Today you can argue that the moral is obsolete)

Or put it another way, you cannot talk about kids having sex without everybody bringing their own different morals up. The two are very intertwined.

Yeah okay that doesn't exactly equate to lacking moral fortitude. Think you're projecting a bit there.

fair enough. I should have put moral fortitude in quotes.