Girls are funny sometimes. One girl I dated wasn't worried about condoms cause she thought she couldn't really get pregnant since she was, in her words, a 'little runt' born to old parents. She also didn't know the pull-out method doesn't really work. I always assume girls are pretty in the know with pregnancy possibilities since they're the ones that could get pregnant and have to deal with it regardless whereas a dude could skip out, but I've been proven wrong a few times.