Quote from Rachel in The One with Monica's Boots
Joey: Well, what am I supposed to do? Rachel: You're supposed to realize that they are adults and they can make their own decisions. Joey: No, they can't. They were stupid enough to get knocked up. Rachel: Hey, contraceptives are not always effective. Right? Bobby: Yeah. We kind of didn't use any. Rachel: Oh, come on, kids, a little help here!