22 Sibling Rivalry

After a pregnancy scare, Peter agrees to get a vasectomy, but before the surgery, he goes to donate his sperm in case he and Lois wants to have another baby in the future. However, while donating his sperm, he accidentally knocks a large rack of samples over and replaces them himself so that he won’t get in trouble, with one of his own. One of the recipients of his sperm is a lesbian couple, who give birth to Stewie’s half-brother Bertram, who appeared in Emission Impossible. Meanwhile, after the vasectomy, Peter does not have any interest in his sex life anymore. Lois does not like this and takes out her frustration by eating and because of this, she becomes fat. When Peter ridicules her for the weight gain, Lois points out that he is way fatter than her but Peter blatantly says that men can't be fat. Angry at her husband, Lois' eating out of frustration turns into eating out of spite as she deliberately puts on more weight, eventually becoming about the same size as Peter, if not more. In bed one night as they try to ignore each other, they accidentally have sex and because of that, their sex life is restored.