I share your pain
I get a kick out of it though. I was tired of hearing the "Girls don't play Games" line. I run my own vent so that tends to clear that problem up relatively quickly. Most guys are ok with it, because I play a healer. Everyone needs a healer right?
I like to play with them though. I recently rolled a male tauren in wow. He's a druid named Anastasiah. Basically I get to run around in the form of a cat, guys flirt with me because of my name... and then I turn into a giant male cow. It really upsets those silly boys. It is odd how when they find out you are a girl they avoid you like the plague for a while.
Boys are pretty competitive, and to learn that a girl just beat them does tend to upset them. But hey! Anything you can do, I can do better!