English is not my native tongue so this is a honest question.

Is referring to someone as "that guy" gender neutral?
If not then what would you suggest would be gender neutral term in situations where you're not sure who's playing the character?

As a side note I'm NOT a roleplayer but I do think that using chat is our characters talking to one another so using the gender of the used character is preferred.
HOWEVER rarely if EVER do I even seen the character I'm talking to. My player character names are switched off (the game looks so much better this way!) so the names I'm sending the tell to are names I see on my pt list or chat box. There is NO WAY to tell the sex of that character unless the name itself is very feminine. I guess what I'm trying to say is that I've made the "guy" assumption sometimes too but NOT based on the character's appearance or sex at all.