In your case load of girls have been pregnant way too early and seem to be looking for a man to fill that 'empty space', have you seen any of them with caring fathers of their own?
My premise is that it isn't as much the mothers of these girls who are letting them down as it is their own fathers. Without the love of a father, a girl will try to find that love elsewhere.
I think it is the family dynamic and the fact that solid, stable, two-parent families have become the exception. Many single parents are able to find healthy ways to compensate for the lack of the other parent, but it is never ideal. Children are being raised by day care centers and public schools, which are all too often more part of the problem than of the solution.
There are no easy answers. Those who know right from wrong need to be an example and teach as much as we can, but until there is real change in the hearts of people, I don't foresee things getting any better in the near future. A lot of the children I see having children came from parents who had no parenting either. These kids have all kinds of problems. Many never developed properly in the first place because their basic needs were never met. Many have attachment disorders because they never bonded with their parents. Child neglect has far-reaching consequences, but all too often, society's solution is to put a bandaid on it. No one is willing to confront the root causes because that would fall under "moralizing" and "judging." Well, some behaviors SHOULD be judged.