1. What is your opinion on girl gamers?
I am one. It has it's own subculture as well -- 'gamer girls' versus 'girl gamers', for example. But that is pretty equal to a "guy gamer" versus a guy who plays one game on an Xbox and calls himself a "gamer".
2. After finding out an opponent or teammate is the opposite gender, do you feel different about them?
Okay, this is odd - the answer is yes, and I've always been aware of it. I'm going to include all MMOs in this example and try to explain.
Number one, their general social behavior is going to be different, because men and woman tend to be raised differently. As a 'tomboy' with four brothers, I never related well to other women in social settings in my entire life save in very rare circumstances - mainly only if they had upbringings similar in enough ways to my own what we share some personality patterns.
(Ask some of the other ladies about the rather explosive arguments we've had on and off over the year - because I don't 'fight like a girl' the altercations tend to be relatively short, highly violent, and discarded afterwards - by me anyway - instead of the stewing on topic X for years (ie. a more 'masculine' way of handling it - after a few punches are swung and noses are bloodied by brain says it is time to laugh it off and drop it.)
Number two as I was raised with some 'stereotypes' especially in the fantasty genre, it was always apparent to me that even if a male player was playing a female character who was "main tank" there was always some added nervousness. It could have to do with the art of teeny little women and giant raid mobs, versus slightly larger men avatars, but who knows.
3. Do you feel gamer girls are their own clique within gamers as a whole?
They try to be at times. I avoid those groups. They simply end up a digital version of high school girls, which I again never fit in with.
4. Do you feel there is a rivalry or alliance between the genders in the gaming community?
That I've never actually detected.
5. Do you feel sexism is an issue, and if so, have you experienced it?
"Trolling" and "flaming" is universal. Sexism is an easy attack point. Usually only takes a girl about thirty seconds or less if she is competently skilled at the game to make her sex, gender, whatever, a non-issue. A lot of words are thrown around the gaming subculture who's definitions are skewed into 'new slang', for example "That's so gay" is rarely referring to homosexuality, but to something ludicrous or unfair, for example. Part of my brain had muddled over whether it didn't end up shifting in definition due to unrighteous persecutions over people in that gender-group, and when something is referred to as 'gay', it is this larger more "meme'd" definition of "Rediculous thing happening that is unfair for no reason" - especially since a good part of the "gaming/MMO subculture" also seems to include a higher percentage of people who are part of other existing subcultures. I know when I say something is gay I am not referring to it having intimate relations with something of the same gender, but being "unecessarily unfair and/or rediculous" - and that's not the same definition of the word.