Equal Pay and Compensation Discrimination
"The right of employees to be free from discrimination in their compensation is protected under several federal laws, including the following enforced by the U.S. Equal Employment Opportunity Commission (EEOC): the Equal Pay Act of 1963, Title VII of the Civil Rights Act of 1964, the Age Discrimination in Employment Act of 1967, and Title I of the Americans with Disabilities Act of 1990.
EEOC
The Equal Pay Act requires that men and women be given equal pay for equal work in the same establishment. The jobs need not be identical, but they must be substantially equal. It is job content, not job titles, that determines whether jobs are substantially equal. Specifically, the EPA provides:

Employers may not pay unequal wages to men and women who perform jobs that require substantially equal skill, effort and responsibility, and that are performed under similar working conditions within the same establishment..."