Humans managed to figure things out for themselves for millennia before PP got involved. Micromanaging the sexual education of millions of American children sounds about as workable as Social Security, just about as efficient, and just about as effective. Nothing like big government to help the young. (/sarcasm)
Just a question--if the government can't even teach kids to read and do elementary math, what makes anyone think that they can do anything about illicit pregnancies? I think that taboos worked much better -- at least taboos were basic, taught from the earliest years, reinforced at home, schools, and in churches, and affected the behavior of young people until they were close to being on their own...
Just speculating here, of course, and only assuming that the reader thinks abortion is a BAD thing, which is by no means certain.
I also know that the such conflict and guilt over sexual desire is almost exclusively a feature of the Judeo-Christian cultures. You hardly ever see in other cultures that have not been infected.
Another thing to consider is that at the time of the origins of the Judeo/Christian taboos, people got married at a very young age thus really never faced the issues of having to surpress their teenage sexual desires.