To those saying, "Why is this necessary? This isn't fair!", Well, here's your answer: http://xkcd.com/385/ (XKCD nailed it, as usual.)
We are on the internet, I can't see you, I have no idea who you are.
EDIT: Oh, do you mean that women should hide the fact that they are women online when contributing to OSS? I imagine many do.
If the gender is not apparent, then there's no real way to discriminate is there?
This especially goes for HN. I have no idea who is man and who isn't, as most use some sort of username/alias instead of their real name.
If the code's good and you can advocate for it - great.
If it sucks - it won't be used.