There are tons of girl gamers and they usually keep a better conversation then most dudes that I talk to. The thing that I've noticed is that the definition of "gamer" is really odd nowadays.
Like, a girl that can play a JRPG for almost 100+ hrs on one playthrough could be considered a gamer, but a "hardcore" gamer is someone that plays all the major titles that you'll probably forget about in a couple of months. Some male "gamers" call themselves that due to the fact that they play Halo or CoD religiously.
It's like, you aren't a gamer unless you put hundreds of hours into the multiplayer of the game. That's kinda why I like Yahtzee's reviews since he focuses mainly on the single player aspects.
One thing that truly irks me are those girls that feel the need to "prove themselves." Like that Mrs. Violence chick, that said something along the lines of "I'm a girl gamer, and I wanna prove that girls can play video games" on the Controller, that Battlefield 3 webseries. There are plenty of games out there, but FPSs shouldn't be the genre that make you a gamer.
Believe me, I've had so many more intense moments in Catherine and the Persona games that had my heart beating so fast due to being nervous or accomplishing something then in any "hardcore FPS."
My girlfriend is pretty poor so whenever she comes over to hang out we spend all our time playing games like Zelda or Arkham City (both of which she beat). She even beat Persona 4 before I did and I'm the one that owns it! I think it's safe to assume that she's a gamer, even with her measly 6 hrs of CoD: BlOps online playtime.
Sorry for the tl;dr essay here, but I feel like needed to get my point across. Plus, I have nothing to do at work right now, soyea.