Well those are good points to consider. Well, how do you know it isn't sexism in the workplace causing this gap? According to research done by Professor Lawrence Kahn at Cornel, there is a 9% unexplainable gap between women's and men's pay after factoring in human capital and gender differences in the workplace. That 9% could be any number of things including discrimination (
http://www.theatlantic.com/business/arc ... ss/263776/), so it seems unreasonable to completely write that option out. The article lists other factors such as negotiating skills or difference in motivation, that could account for part of that 9%, but that could also indicate that discrimination is ultimately taking over. What we think of as "Masculine" skills such as assertiveness and determination are ultimately valued, and because these traits are deemed in our unconcious minds as "masculine", women are not trained to master them as they grow up, and therefore cannot earn the money they want and deserve - the glass ceiling.
The article also addresses the issue of unmarried men and women working the same number of hours. The statistics do not take into account age, which only accounts for younger people. As people get older then, there are many other factors thrown in there such as women having kids and not being promoted as they age, etc, which then creates a gap.