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.
Also if said son actually turns out to be a daughter it tells her that being what she is is so bad that she should hide it from everyone.
cant wait for natural selection to take out slow walkers
YOU’RE NOT A CAT
YOU DON’T EVEN FIT IN IT