The use of "them" as a gender-neutral pronoun goes back hundreds of years, but the weaponizing of grammar as a way to tell people how to talk (rather than a way to understand what speakers are saying) made the practice anathema, creating strong headwinds for people looking to adapt usage to accommodate a spectrum of gender identities.
The Associated Press has got on board with "them" as a pronoun, at least in a small way, with a modification to its influential stylebook allowing for a singular them or they in the case of "people who identify as neither male nor female or ask not to be referred to as he/she/him/her" where it is impossible or awkward to "use the person’s name in place of a pronoun, or otherwise reword the sentence" — but only if you're sure to "explain in the text that the person prefers a gender-neutral pronoun."
Even with the guidance, however, people trying to follow the style guide will have a lot of hoops to jump through, Zimmer said. Still, the change shows a growing awareness of an issue that reporters are increasingly covering people who are non-binary. Usage can also be confusing for readers, Zimmer said, so properly explaining why it's being used will help everyone get used to the idea that "they" could refer to a singular person."Style guides sometimes move in baby steps," he said. "This seems to be a step in a good direction, even if it's not a full-throated endorsement of singular they."
AP style change: Singular they is acceptable ‘in limited cases’
[Kristen Hare/Poynter]
(via Naked Capitalism)