The wage gap is born out of very unsophisticated economics. To reach the wage gap conclusion, you must take all the money that men earn and all the money that women earn, add them together respectfully, and perform some simple division. This doesn't account for the fact that women make different choices than men. Women are more likely to go into fields that pay less than the fields men are more likely to enter, many women take time out of the work force to have children, women tend to work less dangerous jobs, women tend to work less hours than men (on average), as well as taking more and longer vacations (on average.) In short, men and women invest in their human capital differently. When you look at men and women working in the same field, with the same level of experience, the same education, etc. the wage gap evaporates. This video explains it pretty well, just ignore the bits at the end about women being guided away from subjects like engineering, as that is as true as the wage gap, women who go into such fields are lauded by feminists and progressives.
https://www.youtube.com/watch?v=kWIZeNr2rtU