brushyourteeth wrote...
I don't think this is necessarily evidence that there are an equal amount of female gamers as male ones, but I can honestly say that though I'm a pretty obnoxiously extroverted type of girl, I often keep my gaming to myself in conversation and have since junior high school (back in the 90's).
Reasons:
1.) Girls and guys both often seem to perceive that girl-gaming is intended to be nerd-sexy. That's not why I game, and "that's hot" isn't the response I've ever wanted when mentioning my favorite hobby.
2.) In a room full of guys who are gaming, a girl who speaks up and says "I'd like to play" is apt to feel awkward barging into the "boys' club" (eye-rolling ensues)
3.) Even when gaming online, I often choose not to reveal that I'm a woman and/or refuse to use a mic because
- my performance will be scrutinized in a way it wouldn't if I were a man
- I will be flirted with
- I will be coddled or treated as if I'm a beginner that needs extra protection
- (some) male gamers will be incredibly angry to be beaten by me because of my gender
- I have actually been kicked before. Just for speaking into a mic, which reveals that I'm female
So while the numbers may not be equal, they may be higher than a lot of guys realize since maybe girls don't speak up about it.
So I can't say that I'm super offended by the way that advertisers appeal to male gamers, but I have learned from experience that I'm often not treated as an equal or welcome member of the gaming community.
Which sucks, because I love gaming as much as anyone. And I'm good, dammit. 
The numbers may also be skewed in some instances because of females listing their gender as "male" or "undisclosed" on their profiles in order to avoid harassment.
Back in the old days when I used to play multi-player online, I listed my gender as male, used a male-sounding username, a male avatar, and played exclusively male characters because I got tired of juvenile comments about boobies. In other words, bullet point 3 definitely applies.
I've been a gamer since I was 9... tabletop DnD. If they had computer games in the mid '70s, I didn't know about them. My cousin bought my sister and me the first DnD boxed set because she thought it would annoy my mother. In high school and college, my gaming circle expanded to include people outside my immediate family and most of the people in it were male, but then again, most of my friends were male, so that means nothing. I didn't get into computer gaming until around 2005, and that was because my PnP group disbanded.
In perfect honesty, I never really expected equal representation in games, although I'm delighted when I find it. I came to gaming from a PnP culture, which was and may still be male dominated. You don't get as much harassment in a PnP environment, though. Maybe it's harder to be an ass to someone without the anonymity of the internet.