While I certainly don't dispute (or doubt) this logic, at least as being in operation much of the time (MMORPGs complicate things; because of the social-metagaming effects; but definitely in single player), I have to wonder if relative levels of acclimatization to dubiously realistic body models also has an effect.
I don't just mean over-the-top chainmail-bikini-barbie stuff (though female avatars do tend to be even further removed from reality than the male mysteriously-nimble-despite-being-musclebound-about-350lbs-and-coated-in-steel types); but some sort of subtler effect.
I ask because I've been hitting the Bethesda RPGs pretty hard lately (a little bit of Oblivion, mostly for the Shivering Isles, and the arguably superior Dark Brotherhood questline, Fallout NV basically for all the reasons, and Skyrim for when I really want to get my Dovahkiin on) and it's oddly difficult, even with considerably futzing on all the sliders, to get a male avatar who doesn't look just... kind of weird, while the female ones seem to fall into 'yeah, that looks like someone and/or a plausible wood elf' much, much, more easily. I can't really put my finger on why; but spinning a male avatar that doesn't push the 'eh, something's off here' button enough to be distracting is really tricky, while avoiding that with a female one is trivial (except Kahjit, the cats-with-human-breasts thing is just weird, while the male ones look less discordant and have the sense of serious-muscle-under-fur-and-possible-laziness that cats possess).
I don't know if this is just their engine and/or art team, or whether cultural exposure to massive amounts of airbrushed women in media makes it easier for me to be lulled by just one more woman-as-designed-by-artists, or whether my roleplay-fu is not entirely strong and some aspect of years of experience in being male makes me extra sensitive to relatively minor weaknesses in character rendering.
My sample set is small and biased, definitely; but it is something that has puzzled me(doubly so because the male NPCs all pretty much look fine, it's just generating a PC that gives me hell). For some reason, getting verisimilitude sufficient to not nag at me is just easier with female NPCs in those games, while the male NPC attempts just don't turn out terribly effectively (except for my larcenous, salmon-crazed, battleaxe-wielding Kahjit, of course. He's ok.)