This made me think. Could the pay difference be because men work more hours? There are more woman with children with part time jobs vs men with children. This is just a thought.
A favorite trick though from the radical feminists is to lump all the men into one group and all the women into another group and then compare the two. Always, the men will come out on top simply because of biology. Women stay at home more than men starting with pregnancy, then staying at home with the toddler, a lot of women also choose to work less than 100% in order to be at home with their children, etc.
The argument that the data supported is as follows: fewer hours worked (counting the expected or not unpaid overtime) led to smaller raises and fewer promotions. Subsequent raises and promotions are based on the resultant salaries and titles, leading to a snowball effect. Maternal leave puts the whole process on pause and puts a mother behind on the snowball process.
think about it for high paying professions such as top law firm work, or an investment bank -- getting ahead to make partner means working tons of hours which is not a viable option if you have a kid (unless there is a stay at home father).
There are statistics that give pay per hour, too.