Gender Neutrality and Gender Indifference
A quick note about “they” in colloquial English. It’s used for two purposes: (1) when the speaker doesn’t know the gender of the referent; and (2) when the speaker doesn’t care about the gender of the referent.
For example, if I see a cell phone in the aisle of a plane as I’m exiting, I might pick it up and give it to a flight attendant, explaining, “I think someone dropped their cell phone.” I use “their” because I don’t know if it’s a man or a woman.
But equally, if I want to tell you about a phone conversation I had last night, I might tell you, “I was talking to a colleague yesterday and they said the most interesting thing….” I use “they” not because I don’t know who I was talking to, but because I don’t want to emphasize their gender. (See? I did it again. “Their” gender.)