A human's reproductive peak is late teens to early twenties, not mid-teens. Read a book. Or get a bachelors degree in human development like I did. Either way, sixteen-year-olds are not developed enough to have children as successfully as someone just a couple of years older.
Also, blim, that's close to true, but sexual peak is not the same as reproductive peak. A woman's sexual peak is significantly later than her reproductive peak (mid to late thirties).
And, black orb, we understand you, we just all think you're completely disturbed. The people in the future will not find pedophilia/necrophilia/rape acceptable forms of sexuality. Society has been moving away from those things, not towards.