Male here.
Often female characters simply look better than their male counterparts; ranging from their outfits, to their language, and demeanor, to their available inventories. Playing as a female character, more often than not, is simply more enjoyable.
In essence, the character I select to play through a game with, is simply the best looking/best fitting to my play style, that is available; regardless of gender. Coincidentally, females fill that roll more often than males.
A good example of this is as follows:
In Elder Scroll Games I most commonly play as a male, given the 'special' armor designs of the females. Whereas in Mass Effect games I almost universally play as a female, as Shepard looks better that way in my eyes(armor, dialogue, etc.).