The correct way of saying what's good for the goose is good for the gander is what's sauce for the goose is sauce for the gander.
Definition of what's sauce for the goose is sauce for the gander.
If something is acceptable for one person , it is acceptable for another (often of the opposite sex ).
1670s, figuratively using goose /gander for women and men, and literally meaning that the same sauce applies equally well to cooked goose, regardless of sex. Early forms include “as deep drinketh the goose as the gander" (1562) and similar “As well for the coowe calfe as for the bull" (1549).
The expression appears in Dickens when a spy attempting to evade culpability insists, “For you cannot sarse the goose and not the gander."
Source Wikidictionary