This thought was inspired by a post by Njessi of Hawtpants of the Old Republic.
With the increasing amount of cosmetic gear and options like transmogrification in MMOs, has it become easier to guess at the gender of the player behind a character?
It's a total stereotype, but maybe women are more likely to put effort into making aesthetically pleasing costumes for their characters. Especially some of the more subtle outfits.
Certainly, the vast majority of female characters wearing bikinis and outfits that show a lot of skin are probably being played by men. So merely not wearing a bikini shifts the odds of a female character being played by a woman. And maybe men are more likely to wear "achievement" gear or martial gear, like items with a lot of spikes, or Sith armor. Or maybe not.
I just found this idea interesting because it doesn't appear before cosmetic gear. Before cosmetic gear, a character wears her most powerful gear. Gear at that point tells you more about what the character has achieved than anything about the player.
Cosmetic gear, on the other hand, is a window into the tastes of the player. Thus it says a lot about the player, and maybe more than some would want.