1. Men and women receive equal pay for equal work when hired for the same position with the same experience and producing the same outcome. No one says, "You're a woman, 10% less".
2. Most of the "pay gap" is an average of all women's earnings versus all men's earnings - and more women work part time while more men work overtime. The person working 60 hours a week should make more than the one working 30 hours, if doing the same thing.
3. Men with less education are more likely to be in dangerous semi-skilled and low skilled jobs like construction, forestry, fishing, skilled trades, while the women are more likely to be office workers, childcare, elder care. Both have a high school diploma and a little education afterward, but his work is more physically demanding and dangerous - so she makes minimum wage while he makes 1.5 times that. If she dug ditches, too, she'd make more - but few women do.
4. Young women without children make as much as young men without children. You see a drop off in wages when women start to have kids, because more of them drop to part time or don't travel or work overtime. Employers pay more to the person working 60 hours a week than the one working 40, even if both are salaried, in the form of greater raises and promotions. And this isn't gender bias, because childless women keep up with the men when they work the same grueling schedules.