You ever hear the (sitcom) joke "After civilization falls, we're going to have to rebuild, to make lots of babies, but we're going to be safe about it, we're going to need a lot of condoms."
I also remember some sitcom where the fellah forgot that he had had a vasectomy after months of trying to get his wife pregnant... It might have been the John Laroquette Show, which was of course about the continuing story of a recovering alcoholic who had lost decades to black out drinking... "OH! That was a Vasectomy? Hell! I thought that was when I got my tonsils out. Look, I'm really quite enjoying myself, can we tell my wife about this next month?"
Caretaker was so addled from dementia that "he" couldn't remember if "he" was a man or a woman which is why "he" hedged "his" bets by shagging a boy and a woman during the course of Caretaker. Seriously the old coot rogered Kim, psychically assessed if forty-watt was preggers, then penetrated the Klingon with his indistinguishablehood just in case "he" had been a man after all to stick a bun in her perfectly shaped oven.