The most obvious is how the trisolianas quite literally feminize the human culture/population in an attempt to make humanity weaker. Also the whole plotline where they have to pick a new person to hold the button keeping the transmission of their planets location going out. They make a huge point of arguing a woman can not do it (because to push the button would mean both earth and trisolarios would be destroyed) but in the end the humans vote for a woman to do be the next person to hold the button, and then it turns out they were right and she is unwilling to push the button after the trisolans start invading the earth again. Literally right when she is voted in, they start invading. Also a lot of the female characters in the book like the main dude’s wife in the first book are not really fully fleshed out characters and are more just objects for the guy to try to possess/protect.

Its been a little while since I read the books but that’s the stuff I can think of off the top of my head.