Telling your son not to “be such a girl” lets his sister who overhears the conversation know that being a girl is not a good thing and she should be sorry and ashamed of herself.
It also reminds your son that being a boy is better than being a girl and therefore he is better than any girl he will ever meet.
In russian if you cry you get called a cabbage. Vote to change “dont be such a girl to “dont be such a cabbage” say I.
I once had a health teacher who showed us a Family Guy episode to deal with the topic of sexual harassment. The episode made fun of women more than it did anything useful. He then said that women who were offended by misogynistic jokes should get a sense of humor.
(submitted by anonymous)