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20 most popular books on TwoChromosomes (2019 Update) rank no. 20
This is going around reddit today.
It is the incorrect idea that, man is polar opposite to woman, and that man > woman. The next thing to derive from that thinking then is masculinity > femininity. Then masculinity = strong and helpful, femininity = weak and frivolous. Etc, etc.
But in regards to the homophobia comment, it is true I think, a lot of straight cismale homophobia results from some low level knowledge that they have ingrained in their social conditioning an oppositional sexist view of the world.
edit: added links