This seems to be a hot topic running around the blogosphere, and appears to have started with Larisa regarding girls in gaming.
From my experience, women do often times get treated differently. This is not their fault. They did not choose to be born female, and should certainly not have that used against them for any reason in game.
I have played with MANY women over the years in WoW. Most of the were very good players. In fact, during BC, three of our mainstay raiding healers were women, and we had a few others filter in and out during that time. One of them is now one of out top DPS as a Huntard. The fact that they are women has nothing to do with how they play.
I have seen women players who were very good and I have also seen the very bad. There are bad male players as well, but I think that when women are bad they stand out due to the fact that they ARE women. There are a lot more women playing games these day, but they are still seen as somewhat rare. Sometimes, when a male player knows that a player is female, they will be overly critical solely for the fact that she is woman.
As for me, I call the shots as I see them. If you suck, you suck regardless of if you are a woman or a man, and I will say as much. The former healer turned huntard used to be a pretty bad player. It was not that she did not know how to heal or even DPS, but she did not have situational awareness, and did not know of the resources outside the game. She would back into mobs, shoot mobs that we were not killing yet, and have her pet on aggressive which caused it to attack Magtheridon's Channelers and cause the event to start, wiping half of the raid (true story). A good dose of BRK and she became a much better player.
There will come a time when women are not treated like "ZOMG A GURL LULZ". That time is fast approaching. Women in my guild get treated exactly the same as the men. We don't act differently around them, don't hold them to a higher standard, and don't let the get away with any more than a male player. It is time that everyone else got with the time and realized that people are people regardless of reproductive organs.