Women often simply don't know how much they're being underpaid because a large percentage of Wall Street salaries are based on bonuses that are kept secret, she said.

"A lot of people talk about Wall Street being a meritocracy," Roth said. "But it's not always true."

Among occupations requiring advanced degrees, female lawyers, who reported annual median earnings of $97,964, made 78 cents for every dollar earned by their male counterparts. Female university professors, with a median salary of $55,292, earned 80 cents for every dollar. They suffer professionally when they take time off to provide care for children, aging parents or both, said John W. Curtis, director of research and public policy at the American Association of University Professors.

'Gap Hasn't Budged'

The percentage of full-time female university professors has grown to 28 percent from 10 percent in 1981, according to an April study by Curtis. Women made up 57 percent of undergraduate students and 59 percent of graduate students in 2009, the association reported.

The organization has tracked pay disparity for three decades now. "The gap really hasn't budged," Curtis said.

Many women are happy to trade travel-heavy, intense jobs at major law offices for those that offer a higher quality of life, said Mary Cranston, a retired senior partner and former chairman at Pillsbury Winthrop Shaw Pittman LLP in San Francisco. High- end law firms offering large salaries are still predominantly male.

"That's changing gradually, but it's a long, slow road," Cranston said. "I don't know when pay equality will happen."

Doctor Salaries

Lower pay for female physicians and surgeons has usually been attributed to the number of women who go into lower-paying primary-care specialties, according to a February 2011 Health Affairs article by researchers at the University of Illinois-Chicago, Northwestern University and Yale University. Yet their study found the pay gap persisted even as the percentage of new primary-care doctors who were female dropped to about 35 percent in 2008 from almost 50 percent in 1999.