Fanfiction readers tend to be female. HPMoR has attracted mostly men. I'm skeptical that your strategy will influence gender ratio.
Possible data point: are Luminosity fans predominantly female?
Wait, the question isn't in HPMoR attracted more women than men, it's if it the women to man ratio is higher than other things that attracts people.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.