What’s good for the goose is good for the gander
There is a whole host of proverbs that proclaim that what is good for a man is equally good for a woman and they all date back to The Middle Ages and before. They all use the analogy of various animals such as cows and bulls, ewes and rams etc, meaning that what holds good for the male of the species must hold good for the female, although in this particular instance it is the other way round because gander is, of course, the male goose. Although ‘what’s good for the goose is good for the gander’ seems to be the more common form these days, the earlier form of the proverb was ‘sauce for the goose is sauce for the gander’ which first appears in John Ray’s Collection of English Proverbs, published in 1670, where he states it is “a woman’s proverb”. If it was already a proverb by 1670, its origin is probably a lot older.