Women and cats will do as they please, and men and dogs should relax and get used to the idea.

Heinlein’s quip plays on a comic analogy: cats are stereotyped as independent and untrainable, while dogs are stereotyped as loyal and compliant. By pairing women with cats and men with dogs, the line asserts (half-jokingly, half-provocatively) that women’s autonomy is a fact of life and that men who expect control or obedience are courting frustration. The imperative to “relax and get used to the idea” frames acceptance as wiser than resistance. Read charitably, it can be taken as a backhanded endorsement of women’s self-determination; read critically, it relies on gender essentialism and animal stereotypes to make its point.