Ursula K. Le Guin's 1969 novel The Left Hand of Darkness was a big deal in feminist science fiction for being one of the first widely popular and critically acclaimed works to do cool shit with sex and gender (which was certainly nothing new, but previous such works had rarely "taken off" the way LHoD did). It was criticized for referring to the genderfluid characters with the indefinite "he," which was a la mode in style guides at the time, instead of using alternating or gender-neutral pronouns. In time Le Guin came to agree with this criticism; she considered her decision not to take things further one of her biggest literary regrets, stating that "I am haunted and bedeviled by the matter of the pronouns."
I tell you this only because the phrase "I am haunted and bedeviled by the matter of the pronouns" is one I think about a lot.