Much of what Skud (Kirrily) says is without a doubt true, but doesn't apply sole to women. It's generally the way it "works" in the open source world and between developers in general. There is a certain attitude that is simply there, not just between language fanbois but also between developers in general. Your sexual orientation, sex, hair color or religion has nothing to do with that. Partially I think the attitude is there to improve yourself, at least that's how it works for me. You try to be as good as the one you think is better then you are.
In a lot of communities, you don't explicitly mention your gender. You simply join a community (subscribe to a form or e-mail list) and you start posting/reading etc. And unless your nick is 'Girlygirl99' it's not too obvious in name also, so I wonder how people treat anyone based on their online identity. Feel free to prove me wrong on that, it's not that I don't believe it, I simply have never seen discrimination towards sex or sexual orientation in any community I've been in.
And maybe it differs a lot per community, I'm involved in the PHP community and from what I hear it has a small percentage PHP developers that are female, and they even have their own "support site" PHPWomen.org. And they seem to do pretty well.
As Skud quotes in her talk, some projects have a "diversity statement". I think it's nonsense to mention it at any community/project. It should only be mentioned if it doesn't say "everyone". If you want to be part of a community, simply step in. Order a beer, listen and join the conversation. If you lack the assertive skills to do that, it's not something the community can do about. It's something you need to improve on. If a community helps beginners, well that is a (big) plus.
Personally I don't care what you are, as long as you aren't (secretly) part of Skynet.
I agree that gender of community members is irrelevant but sometimes interesting I mean that it is nice to know who are you talking to, because only this can give your partner real human face. With anonymous way of chatting there is always danger of treating other person as his gravatar - like an object. Every human being should have his face and identity not to be recognized by enemies but to be fully human in a world where no human can really enter (we all sit in front of screens, not inside).