Quote from : The Female Eunuch Book

We can say the brotherhood of man, and pretend that we include the sisterhood of women, but we know that we don't. Folklore has it that women only congregate to bitch an absent member of their group, and continue to do so because they are to well aware of the consequences if they stay away. It's meant to be a joke, but like jokes about mothers-in-law it is founded in bitter truth.