I am not much of a gamer lol. So I can only say a little about this. I played the new Bungie game some, made it up all the way to level 7 or 8 before I got bored! If they want more female players they need other things to do that shoot monsters, for example a clothing vendor and a dance club would be nice! The only social thing I can do is dance in the tower and my character looks like a stripper when she dances :) Everybody is different but I think if you want a lot more girls playing a game, you need the game to consider female preferences greatly and I don't mean just pink stuff I mean more social stuff and things to do other than fighting. Other games have more of that balance I am just talking about the Bungie game because we are on a Bungie board.
Even if you do that I think the numbers still might not be equal, I think girls have different outlets whereas I see guys get into playing games for hours and hours. I am just talking about mass numbers everybody is different!
I do think you are right about the "girl in room" phenomenon and it isn't only video games, it does make guys act different, that is neither good or bad.