Binary gender systems are constructed. They rely on the repetition of dominant narratives via psychology, music, popular culture, film and of course children's books. This gem comes from a children's book called, "I'm Glad I'm a Boy! I'm Glad I'm a Girl! It is from the 1950's and I almost appreciate how blatantly obvious it is, since there is no question what it is trying to do. Gender-based messaging is much more subtle and nuanced these days.
You can see the whole book here. I am very glad no one read this book to me as a child, I probably would have set it on fire.
Whenever I see vintage sexism now all I can think of is Mad Men.
Three things a woman always is that always make her NOT man or not HUman. Either you know exactly what I'm saying due to your innate intelligence or good sense, your early exposure to feminism or pursuit of philosophy. Or you don't, in which case enjoy my stream of random stuff/whatever.
Mad obviously irrational.
Menopaused exactly men no longer care.
Mother is the other.