Singular "they" is such an improvement over the "his/her" construct. It sounds completely natural.

I'm from the south, and I'm pretty sure I recall hearing singular they used frequently when I grew up. I know I was using it back in the 2000s before all the drama against using it started. I think a large portion of the AIM/IRC/LiveJournal contingent adopted it pretty early on too.

Anyone gatekeeping this word is either extremely OCD, a total grammar Nazi (which I can't fathom - language is flexible af), or they're turning the issue into a stupid political talking point.

edit: proud to be downvoted by hateful anti-trans/anti-LGBT people. You won't win against love, though. Do what Jesus asks you: don't throw stones and love one another as yourself. I think Jesus would be pretty stoked about using singular "they" if he spoke English.