Perhaps brought on by the news that a Chinese MMO wants to reveal gender bending gamers, Cary posted a pretty interesting poll over on the WoW LJ, asking readers what their gender is and what sex they play as on their main character. The general consensus seems to be that most people play as their own gender, but overwhelmingly, more women play as their own gender than men. The poll itself seems a little off to me, as it's really pointless to compare the percentages given, but by crunching the numbers a bit (and please remember how bad at math I am), I get that 40% of men who answered play the game as women, while only 11% of women who answered play the game as men. Here's more data on this, that we've covered before.
Very interesting. We've touched on the reasons for gender bending in game a few times before, and there are all kinds of reasons why people play as characters of the opposite sex, from staring at an attractive behind to garnering more money and attention (or less attention) from other players, to roleplaying a character.
But really, none of that matters too much-- it's just a game, and for whatever reason, people are welcome to play it as they please. A better question might be how you refer to the gender of other players. I've gotten in trouble a few times here by referring to players on the forums (including CMs, way back when I started) as one gender when it turns out they're actually another, so eventually I just decided to call it how I see it: if someone plays a female character I call them "her," and a male character gets called "him." For people playing a different gender, sure, it might come off a little strange. But it comes with the territory, I guess, of pretending to be someone else for a while.