I have never once seen a pay scale that has seperate grades for women. The "women make less" statistic is weighted by women taking time off to raise children, that they are more likely to be primary caregivers and less able to do overtime and so on. (Which yes does figure into the problem)

That isnt to say that in jobs where staff can negotiate their own salary or recieve offers there IS DEFINITELY a problem with women recieving lower offers. Also being offered less chances for advancement, etc. But there isnt a company that would ever have the balls to deliberately put a lower pay scale for women on paper these days.