And I know from speaking with my nieces and nephews that teenagers don't care if they get pregnant or not, because they just go get abortions.
If I had to guess, I would say condoms are the number one form of birth control among teenagers, and abortion is second.
Some of them have babies at age 14 (sometimes younger) - I know, because I teach 14 year olds with children, and I teach 14 year olds with mothers under 30.