Williams, who was the first and only Latina woman to head a Fortune 500 company, was named CEO in 2017. Her departure marks the first exit of a female Fortune 500 CEO this year, reducing the already scant number of female top executives in the group to just 27.

At an NFL forum held earlier this year for women in sports, Carolina Panthers head coach Ron Rivera encouraged those women to keep pushing to make their football goals reality. "There are jobs for women involved in the NFL and they're not on the outside, they're on the inside," CBS News reports him saying. "They're making decisions."

"Women in male-dominated industries need to prove themselves, and the trucking industry isn't any exception," she says. "When a female professional driver pulls into a loading dock, she's often met with skepticism from the men around her, who watch her as she backs the rig." Petelle says that in her 15 years as a driver she's experienced plenty of derogatory remarks. "I've had men tell me, 'Why aren't you home having babies?'" she says. "And they are usually the older men who are in their 50s and 60s."

As it stands, black women earn $0.63 for every dollar earned by their white male counterparts. Native American women earn $0.57 to every dollar, and Latina women earn $0.54. Meanwhile, white women and Asian women earn $0.79 and $0.87, respectively. "There are a lot of reasons why this gap remains," Elise Gould, senior economist at the Economic Policy Institute, tells CNBC Make It, "and there is certainly room for some of that to be discrimination."

"If a woman has a bad experience in graduate school and decides not to become a professor, that is one less woman who applied to the same jobs I did, and that meant more room for me," he says. "All men have benefited from the reduced competition of women who have been dissuaded from certain careers or certain companies."