Majority of the time, I roll female. I apologize for the cliche', but yes, mostly because I find females substantially easier on the eyes. However, every so often I think a female just suits the role/class better.
Like when male models are stuck as brick-like manly men- they're not really rogue/mage material, if ya ask me. But then again, a lithe female as a knight or paladin or the like? That aesthetic is ridiculously awesome to me. I don't find it "funny" or anything, but... well, I have a female pally on NWN2 that wields a tower shield in one hand, and a friggin' greatsword in the other (via Monkey Grip feat, not hacks 9_9). I can't help but feel super-awesome playing as her...
I guess in the end, I find males kinda boring or... something? I dunno. :S
Anyhoo, I question nothing. There's plenty of reasons for someone to play their opposite gender in any game. Whether a guy wants to leer at his character's rear, seduce other guys for "teh lulz" and loot, subconsciously bring identity issues to the surface, or a lady rolling a dude to avoid attention...
It matters naught to me. /