I've never seen hard numbers on the gender breakdown of SF readers . . . but I would venture to guess that the gender breakdown of SF readers closely corresponds to the gender breakdown of SF writers.
The gender disparity in published SF isn't the result of bias in the editorial story selection process. The gender disparity exists because men, in general, are more disposed to enjoy reading SF than women, in general, are. More men than women enjoy reading SF, and thus more men than women write SF. - Sam Hidaka
Let's review, cause I'm a female engineer, I have with the maths! Here's a dude talking about something as though he knows what he is talking about after stating up front, straight up, that HE HAS NEVER SEEN THE HARD NUMBERS and thus in fact KNOWS NOTHING ABOUT THIS. Ah, that's good to know. Cause that means that, based on no facts, the patriarchy can reassure me that I am in fact not experiencing any prejudice at all. PHEW! I was getting a little hysterical there for a minute. But now?! Now I am reassured. I shall go back into the kitchen and bake some cookies.
See, it's like before women had the vote. Before we had the vote, more men voted than women. True facts!  No, hang on, wait, it's not like before women had the vote. Cause back then, men decided that women couldn't decide stuff for themselves. And so they decided it for us. See here, this is nothing like that. This has nothing to do with the editorial selection process. Well, it couldn't do, could it?! I mean ... after all, he's deciding what I don't want to read for me. Without ever asking me.
Noone actually in the middle of this rather interesting discussion is actually suggesting quotas, lowering the bar (!!) or biasing processes towards selecting women writers. What we ARE suggesting is that editors broaden their scope and taste. We're suggesting that editors consider that the audience is broader and more diverse than just the editor and his/her tastes. we're suggesting editors might want to take a moment to self reflect on what stories they pick and why. We're talking about editors being responsible for selecting stories that appeal across a spectrum of SF readers (which PS would increase sales ...) and not just the ones that conveniently represent the interests, perspectives and life experience of the editor. We're suggesting that editors look out beyond their own self imposed boundaries and explore the Other. You know, like what this genre is supposed to be all about.
 Might more women read more SF if, like, there were more women written INTO the SF? Anyone got a chicken? I have this here egg.