The most effective birth control I know is a toddler with the croup and diaper rash.

The line uses dark, domestic humor to puncture idealized notions of parenting and fertility. By calling a sick toddler—specifically one suffering from croup (a frightening respiratory illness) and diaper rash (a messy, painful irritation)—the “most effective birth control,” the speaker highlights how the exhausting, visceral realities of childcare can temporarily extinguish any romantic desire to have more children. The joke depends on exaggeration and specificity: the more concrete and unpleasant the scenario, the more persuasive the “argument.” Beneath the punchline is an acknowledgment of parental burnout and the way caregiving labor, especially during illness, can reshape attitudes toward family planning.