For thousands of years, women have not had rights equal to those of men. Women could not vote until 1920. In 1923, the Equal Rights Amendment was introduced, ensuring that men and and women would have equal rights all over the United States. Yet here we are in 2017, with a wage gap. Women are only making 80 cents of a man’s dollar, a wage gap of 20%.
The main reason for this is the historical 
idea that women need to stay home and run the household, while the man works and provides for his family. But the reality today is that men and women are able to receive the same education and same jobs. In fact, women are more likely to earn a college or graduate degree than men. But back to the motherhood penalty, many mothers have to take time off work when their baby is first born, because let’s face it, they have to. Many people wouldn’t want a screaming baby in the workplace. A lot of men take off work as well when a child is born. The difference is, men have an increase in earnings while women earn 7% less per child they have. This presents the wage gap.
Another reason for the wage gap is something professionals call lack of negotiation. Meaning, women have less confidence than men to confront their bosses and ask for a raise. This may be the case for some women, but the underlying issue is how women are treated in the work environment. They aren’t seen as equal to their male peers. Deep-rooted stereotypes are to blame. The truth is, women are just as capable of doing anything a man can do.
https://iwpr.org/issue/employment-education-economic-change/pay-equity-discrimination/
https://www.aol.com/article/news/2017/01/21/timeline-the-womens-rights-movement-in-the-us/21659519/
http://fortune.com/2017/04/03/equal-pay-day-2017-wage-gap/