Pregnant Barbie

Alright, listen up, Alastor, you chucklehead. You really asked why a Barbie doll can't be pregnant? You think the plastic baby maker works like that? You do realize Ken and Barbie are just toys, right? You think they're doing the deed in their plastic playhouse? The joke plays on the fact that Barbie and Ken are sold separately and implies that the reason Barbie isn't pregnant is because Ken didn't come with her, you absolute walnut.