I find it more curious that there should be more religious women than there are atheist women. Lets face it, they tend to face a pretty bum deal from most of the major religions. My girlfriend became an atheist as a very young age because she was unwilling to accept the Bible's assumptions that she was impure, or somehow not as good. I suspect a lot of religions get by through providing women with a lot of organizational posts while at the same time excluding them from positions of higher authority (like the Anglicans and their 'controversy' over having women bishops). I've known a lot of women (including my mother and both my grandparents) to simply convert to their husbands religion, rather than stick with their own. Its kind of a new thing in the world for women's religious opinions to be really counted at all, so its only a matter of time before women atheists start to rise to the same levels of prominence as the current batch.