comparable worth

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The theory that compensation for jobs filled chiefly by women should be the same as those filled chiefly by men if the jobs, regardless of how different they may be, have equal socioeconomic value.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The principle that there should be no difference in remuneration between jobs held mostly by women and jobs held mostly by men, when the women's work is comparable in skill, effort, working conditions, and responsibility to the men's work.