Well, granted that gender is pretty irrelevant to the game. It is largely cosmetic, and I find excessive role-players almost as annoying as excessive rules-lawyers who want 23 Attributes, 41 Skills and a little number popping up telling you exactly how many health you have and how much damage you do with each swing.
The player does identify with the character he controls, however - a person watching somebody playing the game would refer to the on-screen character as "you" in conversation, as in "that dragon just fried your ass", rather than "that dragon just fried your character's ass" - and in the case of a male player playing a female character, it just seems odd, and the same thing for a female playing a man. Again, I always get the feeling that 95% of people playing the opposite gender (when the game gives a choice) is guys who are making sure they retain the opportunity to see two chicks kiss. God knows how much of The Sims' sales were driven by this sort of thing.
The Sims actually had its tremendous sales figures because it was one of those games that
didn't sell to an almost exclusively male crowd - in fact, I have seen reports that it was actually more popular with women who are over 40 than the stereotypical teen male crowd. The same can be said for games like Puzzle Pirates - it's just the games that include "Now with 50% more extra-bloody decapitations!" as a selling point that tend to have the 90% young male playerbase.
Now then, yes, obviously a large number of people here are going to say that they play a girl just because they want to stare at a female in a chainmail bikini. Judging by the number of clothing mods for female characters that are made with about 2 square inches of material and the like, this is probably a notable chunk of the userbase, even.
However, I believe that a decent portion of people who say these sorts of things are just unwilling to admit due to social pressures that they actually would like to "get in touch with their feminine side" when they are playing a single-player game that is all about fantasy. If you want to mock someone for trying to play-act out being a stalwart female paladin who defends the innocent from bandits, you are not all that much different than the guy who is play acting out being the hulking brute who can rip wispy waifs in half with their bare hands. In fact, I would say there is far more sixual and emotional maturity to be found in the former than in the later.
If the notion of actually trying to see the world through the eyes of the other gender honestly scares you that much, then it's probably because you've honestly never tried it, and are terrified that you might not think it all that bad.