I think that the global root of the problem is that we as a society do not recognize raising children as an extremely important work that should be respected and compensated. All the gaps will be fixed once there will be the way for women to get compensated for taking risk of child birth and linked reduction of career opportunities. Women do take a lot of risk, just not of the type companies pay for, and there is probably no way to make companies fully cover it. So the question is who and how should do it. Maybe some kind of basic income especially for this purpose would work. It is actually weird that while the idea of the basic income is so widespread, there are no equally popular ideas of using it to fix the gender wage gap problem.