[moocowduckquack]

using "they" to refer to a single person sounds wrong

Yeah, well the person you are replying to, they may disagree.

[67726e]

The use of "they" to refer to one person is incorrect. Maybe things have changed since I was in school, though I'm 20 so I doubt it, but it was never correct to use "they" instead of "he" or "she". The reason it sounds wrong is because it is wrong.