Season 1: Episode 15: The Big Snip
Relieved to find out she isn't pregnant again as she had feared, Christine tries to tighten down on birth control by asking Jimmy to get a vasectomy. Jimmy initially refuses, until he has to cope with the alternative: no sex. As neither can live with that option, Jimmy caves in and agrees to have the procedure. But he quickly develops pre-op jitters, and ends up telling Greg that he isn't as fearless as he's led Christine to believe. Greg takes him to the doctor to have the operation explained to him so he'll see that there's nothing to fear, but by the time the doctor's done explaining, not only is Jimmy terrified of vasectomies, but Greg too. Jimmy finally admits his fear to Christine, and she tells him she'll help him through it. After he's been prepped and ready to go through with the big snip, Jimmy sees her playing with a little girl in the hospital waiting room, and again refuses to go through with the vasectomy -- this time because it would mean they'd never be able to have a daughter.