Definition & Meaning of "what is good for the goose is (also) good for the gander"in English

What is the origin of the proverb "what is good for the goose is good for the gander" and when to use it?

The origin of the proverb "what is good for the goose is good for the gander" can be traced back to at least the 16th century. The phrase was first recorded in its current form in a 1546 English collection of proverbs. The saying uses the comparison of a goose and a gander, a male goose, to suggest that what is suitable or beneficial for one should also be so for the other. It emphasizes the importance of treating everyone equally, without favoritism or discrimination. While it advocates for equality, it also reminds that fairness requires consistency, ensuring that all individuals are subject to the same rules or standards.