Online gaming is like any social gathering, where there are emotionally mature people and awkward, often creepy people who have no interaction with the opposite sex. Not to mention those who are just dickballs for the hell of it.
Add a slather of anonymity to it all and you get the result where women feel they can't really play online without being harassed for their gender. It's very real, but it's a situation where the vocal minority (awkward people, dickballs) drown out the normal players.
If you took a poll of, say, everyone that plays Black ops and asked them how they would react to a female on their team or on the opposite team, most wouldn't say they'd make sexual innuendo or try to pick the girl up. But when you get to a game where a female shows up, the people who think otherwise are the loudest in the game.
So as a result, women tend to hide their online identities if they just want to play in peace. They use voice modulators built in to the system software or simply don't talk because they want to play a game, not be a centerpiece of discussion.
But this also speaks to kind of a major problem with the gaming culture: it is defined as one or two types of people. You're either the bro gamer or the nerd gamer, both presumably white. If you're a different race, a different sexual orientation, a different gender, etc., you're expected to just roll with the harassment because you don't fit the majority mold.
My gamertag includes my name, Imran, and I can't tell you how many times in games (from Team Fortress 2 to Halo 3 to Street Fighter IV) someone has felt the need to make fun of that. Terrorism jokes aren't uncommon, one guy in SSFIV sent me a voice message afterward calling me "a Saddam ass motherfucker".
My girlfriend refuses to play in online games after being chastised for not playing well enough. When she responded with "I think that other guy is using an aimbot," she got laughed at for accusing the other team of cheating, peppered in with some "lol girl" comments. A few weeks later, the guy was banned from the server for using an aimbot.
I don't think things like these would have happened if the harassees were white males that fit the general mold of what we see as someone who plays video games.
Unfortunately, I doubt we'll get to that point for another ten to twenty years at least.
