You hit the nail on the head.
It depends. With online gaming, it can absolutely be better. Unless you use voice chat the other players on your team will only judge you based on your play, not on your gender (which they wouldn't know). You'll probably still be called 'bitch' or 'fag' but that's just the nature of the beast.
But when I game with people who know my real gender, I definitely feel pressured to do better because I'm a girl. It may just be an internalized feeling, and girls who grew up in the 2000s may feel differently, I'm just saying that it's been my experience. Even then I don't see it as a huge deal. It's not something that would stop me from playing games. Still, I can see how it would prevent a lot of young girls from getting into gaming in the first place.
Basically, I think that the issue of women in gaming deserves to be talked about. Like adults. Adults who use facts.
PS - Just an added thought... do iPhone games like Bejeweled, which is played by a lot of women, really count as games? I've heard a lot of discussion on this and I've yet to come up with an answer. I think the distinction between 'casual' and 'hardcore' (or whatever you want to call it) definitely exists. There is a big difference between the person who only plays games on their phone while riding the subway and the person who sinks 600+ hours into Skyrim. I'm one of the latter (but also the former). I guess what I'm trying to say is I'd really like to see numbers on women in gaming based on the hours that they play, because I'm fairly sure that people who fall into the 'hardcore' category have mostly penises.
PPS - Also seeing some numbers on women who follow Let's Plays, MLG and gaming podcasts would be interesting.