I list this as a separate reason because our culture breeds this. Yes, that's right, working mothers. Both parents working causes their kids to be raised by the daycare with the cheapest rate and loosest policy on diarrhea, no pun intended. Because they are the nurturers. I know some fathers that stay home, and more power to them.
Parents divorce each other.
A job that was hard for two, is now made impossible for one. I work, my wife stays home with the babies, and it is the hardest thing in the world to take care of them. No one can do this job alone, no one. Easy, they do a half-ass job of it. Teens having babies.