And in an attempt to un-hijack the conversation - obviously, being male, I'm not on the receiving end of a lot of the attitudes women SF fans have to face. And I try to avoid perpetuating them myself. But there's another issue I noticed which is attitudes among women who are not part of the fandom. I have a very good friend of mine, who I've known for over 15 years, who embodies this very clearly - she and I have been swapping book recommendations for as long as I've known her, but she has always utterly refused to even consider anything that's SF or fantasy. Her husband reads a lot of SF, but she doesn't touch them. It could be that she's simply not a fan, but I've heard her labelling an interest in SF/fantasy as masculine, and I'm pretty sure that's why she never gave it a chance.
Anyway, she is a relatively extreme example, but, growing up, whenever I tried talking about an SF book that I liked to my female friends, they would normally be disinterested and/or explicitly tell me that being women they are not into that sort of stuff. While my male friends - genre fans or not - at least listened. Now, there were also exceptions to this - I had a friend whose older sister was a huge SF fan and quite a few of the books I've read in my teens came from her - but assuming this was a somewhat typical situation I can see why a lot of people will grow up assuming that SF lies firmly on one side of the gender divide.