Well, typically they'd be less likely to be interested in living out male adolescent power fantasies. ;)

If the difference between the two genders is just cosmetic, then I play as a male. It makes it a little easier to imagine myself as that character and makes it a little more immersive. Though thinking about it, some games that gets really annoying. Take Metal Gear Solid. I have to spend all of that time staring at Snake, or Raiden's, butt. And it's not like it's just there. It's there in tight spandex in all kinds of sneaking positions.

If there are benefits to the different characters, I'll decide based on benefits. Usually it's the male, though, as I'm more of a tank player.

And if it's female only, then I'm cool with it.

depends on the game, but sometimes I just make a female avi for something prettier to look at while I'm gaming

I'm pretty sure its more than 1 out of a million lol. 

I'd rather play as a male character if given the option and it has no affect on gameplay elements etc, but I don't mind playing as a female character.

On Sacred 2, the Valkyrie is my favorite class. On Star Ocean the Second Story other than the first time which I've played as Claude, I play as Rena since it cuts out almost two hours of text at the beginning of the game, and you get Dias instead of Leon. My favorite two DoA5 characters are Hitomi and Ayane, but Ein > Hitomi, so Hitomi will get replaced as my main in Ultimate.

Man, I don´t even know ONE female gamer, so, I guess this is the reason.

And by the way: To have Kinect for JUST DANCE or having played Donkey Kong once do not make you a gamer.

I always play as a male. In lot's of games I'd prefer to play as a female but then I feel that I'm being judged every time someone watches me play. Remember that scene from surrogates where they find out the sexy robot that was killed was piloted by a fat bald guy?

The movie plays this up as being disgusting and wrong since that's how the majority of the public perceive it. Now I personally disagree with this opinion, but I'm not going to argue my views. Much simpler to play as a dude and not have to deal with it.

On handhelds I play with dem boobies as much as I can...

As long as the game is good I don't care what sex or race the protagonist is.

You don't mess up the toys of a god.

Depends on the game. I almost always choose a guy unless selecting a girl is canon, like in Star Wars: Knights of The Old Republic II and Perfect Dark. Mass Effect is one major exception though; The performance of the female voice actor (who is also much more experienced) is pretty much perfect while the male is an embarrassment not only compared to her, but compared to all other voice actors in the series.

Well, and Female Shepard also has a great ass and lesbian romance options which admittedly makes the choice a lot easier than it already is.