Quote from Phoebe in The One with the Hypnosis Tape
Joey: Pheebs, he seems to enjoy it. Phoebe: But do you think he's going to enjoy it when he's up to his elbows in the diapers of all the babies they have to have right away? This is not fair to Frank, and it's not fair to the babies. And you know what? It's not good home economics.