Women as a group do get paid less than men as a group. But not for doing the same work. Women average fewer annual hours of work than men. They work continuously for fewer years than men, since only women get pregnant, and most women are not prepared to instantly dump the baby on somebody else to raise.
Being a mother is not an incidental sideline, and being a single mother can be a major restriction on how much time can be put into a job, either in a year or over the years.
People like Hillary Clinton can simply grab a statistic about male-female income differences and run with it, since her purpose is not truth but votes. The real question however is whether, or to what extent, those income differences are due to employers paying women and men different wages for doing the very same jobs, for the very same amount of time.
We do not need to guess about such things. Many studies have been done over many years -- and they repeatedly show that women and men who work the very same hours in the very same jobs at the very same levels of skill and experience do not have the pay gaps that people like Hillary Clinton loudly denounce.