Nope. Sadly, it's real. Sick, isn't it?
Seriously, I would say that most people are not able to actually understand and appreciate the consequences of sex until their mid-20s, at least for women. Men, maybe older.
The reason I postulate this is that prior to the mid-20s, hormones usually trump everything else. That combined with the natural thought process (I'm young and bullet-proof, nothing can hurt me) makes really realizing what you are doing, that children and/or disease and death can be the consequences, next to impossible.
The age of consent should be high enough that kids can be protected from predators. 18 places everbody pretty much off limits.
Sweet Lord. Hard to imagine.