Anyone who has been in a skeptics group knows this discussion. Some dudes (and occasionally a few ladies) decide that it has something to do with the evolution of the mind and the innate ability of women to understand science or logic. Some others say that social pressure makes women avoid scientific subject matter (which has been documented and results in a difference in science/math ability for women depending on their culture). These debates start because there is a noticable lack of women in skeptic groups, but also because statistically women are more likely to be religious or believe in stuff like psychics. Men who are into woo are usually more into conspiracy theories and UFOs, which gave more weight to the social explanation.
When I used to get into these debates, I would regularly fall into the second group, and argue that social pressure has a major influence in the hobbies and interests of women, discouraging them from participating in things like skeptics groups and science. My feminism was still in the fun feminism stage (my feminism was about "choice" and "equality" rather than freedom from an oppressive social order), so my entire range of argument seemed to be contained in those positions. It was either nature, nurture, or a mix of both. The cognitive sciences are not even close to being able to say what is correct, so not much got accomplished during that ever recurring debate.I shelved it off in my mind after considering that, thinking that after discussing it so many time with so many skeptics that I had a pretty good range of opinion and a good grasp of the argument.
I ended up finding a completely new answer in a totally different place. Once my feminism had stopped being something about me personally and more of a tool for understanding the world, the answer became clear. I could think about the question outside of my experience (someone who was already a female skeptic), and instead think of it in reference to the experience of typical women. I read about the way that labor is divided and compensated for, and came to a very obvious conclusion.
Women do the majority of the work around here, and around almost everywhere, actually. There are so few female skeptics because the potential ones are busy. Women are generally doing a lot of work that will not otherwise get done. They are disproportionately dealing with low pay and poverty, and with child and elder care. This means working more employment hours with less pay, and working for free much more often the rest of the time. They are volunteering. They typically don't have time to sit around and ponder things like philosophy and science.
That isn't to say that being busy makes anyone incapable of being active in skeptic groups, it just makes it a whole lot less likely. Having less time and money makes it more difficult to access the same information skeptics rely on to verify or debunk claims. All the extra challenges that women face are in addition to the sub standard science education that the general population receives in the us. There are anti science and anti intellectual culture elements that women deal with in addition to the gendered expectations of their interests. Being exhausted and dealing with practical matters makes it kinda hard to care.
The way I see it, this dudely tradition of sitting around and pondering while women and poor people did all the work started all the way back in ancient Greece. It continued on after that, and continues today. The domestic labor of women is taken for granted, it is how women are excluded from things that would help them develop their minds. Most of the science and technology in the world came to be because there was a vast underclass of people who were not allowed to do anything outside of the really essential labor. The people who benefited the most from the underclass are the ones who were allowed to investigate the world via science and philosophy. When I say science came about because of this system I do not mean that it happened because the system was good or useful, I just mean to describe the means of science. I have very little reason to believe that this was the best or most efficient way to accomplish these things- only a small number of people ever had the opportunity to attempt seriously investigating the Big Questions. Unique thinkers were tossed aside in favor of people who were lucky and incompetent. We have no idea what humanity missed out on.
The folly of that thinking seems like something of the past, but it isn't. There may be no stated rules in place excluding others, but many of the cultural customs create a discriminatory effect that follows the same pattern as the past. I am not particularly interested in the choices of individuals in the culture or why they made them in my take- there are very happy stay at home moms, very committed woos who wouldn't listen to science anyway, etc. That isn't the point. The point is that the social pressures result in people doing what they think they "should", not what they should be doing to gain the greatest sense of fulfillment in their lives- there is a difference that exists because of the cultural attitudes. It has been measured and shown to be real many times. It is the result of our collective inability to dismiss these ideas and fight against them.
This doesn't just mean fighting against the idea that women are not good at thinking about math and science. It also means opposing current ideas about what work is and how it is valued. It means women in their personal lives bringing up the option of delegating domestic labor to men, or demanding to be fairly compensated for it (not just during divorces). Women who can afford to this should, and the ones who cannot afford to this for whatever reason shouldn't be looked down upon for it. It means that the work of women gets to be called work.
This is probably best accomplished via a collective (community or government) payment system, because women need to know that the worth of their labor isn't even restricted to their families- poorly raising children means poorly raised adults live in society with the rest of us, affect each of us every single day. Fathers are not always locatable (and it isn't always desirable to do so anyway). This should be considered a final goal for feminist activism, with steps towards that being taken whenever possible.