That is not to say that the system is rigged against women.
Carnevale points out that many women with degrees in higher-paying fields tend to choose the lower-paying jobs in those fields. Women who are math majors, for example, are more likely to become math teachers, while men are more likely to go into other, more lucrative fields.
Still, it bears mentioning that these career choices don't entirely explain the gender pay gap. Even in many of the fields that women dominate, women earn less than the men they work with, as the Institute for Women's Policy Research showed in a report earlier this month.
However, Baum notes that the tides may soon turn for women, as they have a higher college completion rate than men, and there is some evidence that the wage gap is closing amongst younger workers.
For women who have signed off on their loan papers and are enrolled right now, says Carnevale, the solution is clear.
"The best advice for a young woman is, if she's in a classroom and if everyone else is a young woman, she needs to get out of there," he says.
Danielle Kurtzleben is a business and economics reporter for U.S. News and World Report. Connect with her on Twitter at @titonka or via e-mail at email@example.com.