The phrase "What is good for the goose is good for the gander" means that what is suitable or beneficial for one person should be equally so for another. It emphasizes fairness and equal treatment without discrimination or favoritism. Essentially, if one person is allowed or expected to do something, then another person should be allowed or expected to do the same under similar circumstances. The saying uses the analogy of a female goose (goose) and a male goose (gander) to express that what applies to one should apply to the other as well.

This proverb dates back to at least the 16th century and highlights that consistency and fairness in treatment are important principles. It is often used to advocate for equality between individuals in similar situations, such as between men and women or different parties in an agreement. The phrase also aligns with the ethical principle of reciprocity, like the Golden Rule—treat others as you wish to be treated.

In summary, "What is good for the goose is good for the gander" means equal rights, equal treatment, and that no one should receive special privileges or be treated unfairly compared to others in the same conditions.