Board Thread:Help!/@comment-5532276-20140228232457/@comment-1350697-20170421135438

I think singular they is, at this point, common enough to be the obvious, logical default, and most modern style guides essentially allow it, albeit usually with some disclaimers.

To cite the AP Stylebook's recent update:

They, them, their: In most cases, a plural pronoun should agree in number with the antecedent: The children love the books their uncle gave them. They/them/their is acceptable in limited cases as a singular and-or gender-neutral pronoun, when alternative wording is overly awkward or clumsy. However, rewording usually is possible and always is preferable. Clarity is a top priority; gender-neutral use of a singular they is unfamiliar to many readers. We do not use other gender-neutral pronouns such as xe or ze...

In stories about people who identify as neither male nor female or ask not to be referred to as he/she/him/her: Use the person’s name in place of a pronoun, or otherwise reword the sentence, whenever possible. If they/them/their use is essential, explain in the text that the person prefers a gender-neutral pronoun. Be sure that the phrasing does not imply more than one person.

(Personally, speaking as a non-binary person myself, I've always found "it" immensely dehumanising, like my dissatisfaction with the gender binary means I no longer warrant personhood. Unless demanded by the source text, "it" is, to me, a word for objects, not people.)