The transgender movement is something that has become so prominent and has always been so very necessary. It is starting to become clear to members of our generation that the gender binary is something that not only should be questioned, but outright defied. As a result, linguistically and culturally we are still struggling to change our line of thinking. This is becoming obvious in the grammatical struggle that is happening right now.
Many people who don't identify as part of the gender binary use "they/them" pronouns. This in itself is absolutely fine. However, there is an interesting push back from an unlikely source--educators. As an English major, I have had several professors who insist that singular "they" is not grammatically correct (one of whom had a doctorate and was part of an LGBT committee), to the point of taking points off of essays for its use. And I'm not the only one. Many sources, such as Oxford Dictionaries, don't even breach the topic of non-binary genders; this article says to avoid using singular "they" if at all possible, instead advising to use "he or she" or "his or her". Despite the fact that singular "they" actually does have many roots in grammatical correctness.
The insistence that singular "they" is not correct and the adherence to "his/her" only serves to reinforce predetermined ideas of the gender binary in a world that is beginning to defy its constraints. What's more, even if singular "they" weren't grammatically correct--which it is--it shouldn't matter. Language is supposed to change as our culture changes so as to better suit expression; that's why slang is constantly in flux, and why new words are created every year.
Not to mention, singular "they" flows so much more smoothly than "he or she" in our common vernacular. Take this sentence:
"Sorry, that my just my neighbor on the phone." "Oh yeah? What did they want?"
"What did he or she want?" is awkward, and it takes more effort to say. At the same time, these practices have become so ingrained in our culture that some actively fight for them. As a result, we aren't even allowing transpeople a safe space within our language; we're insisting that our polarized way of thinking is superior, in a subconscious, somewhat reflexive way.