what's good for the goose is good for the gander
From earlier what's sauce for the goose is sauce for the gander (1670s). Other early forms include “as deep drinketh the goose as the gander” (1562).
- What is good for a man is equally good for a woman; or, what a man can have or do, so can a woman have or do.
- What is good for one type is equally good for another type, despite any irrelevant differences between the types.