Down in her comment http://news.ycombinator.com/item?id=2274993 pamelafox linked a blog post she had written about it being good to be a girl in CS, but that post references a previous one she'd written in which she talks about her experience in Model UN in school, where she found herself doing the same thing. Automatically requiring other girls to 'prove' themselves more than the boys before she had respect for them as a speaker. (That post is here: http://blog.pamelafox.org/2009/10/should-i-defend-my-cred-ye...)

I try to be conscious of it, but again, I know what it's like to be on the receiving end. If this is a bias even other women aware of the problem have and have to consciously fight in themselves, how many others (men and women) don't even get as far as recognizing it?