29 CFR 1620.22 : Labor (§ 0.735-1 To Parts 4908-4999) — (Part 900 To Parts 1692-1699) — Regulations Relating To Labor (Continued) (Part 900 To Parts 1692-1699) — Equal Employment Opportunity Commission (§ 1600.101 To Parts 1692-1699) — The Equal Pay Act (§ 1620.1 To § 1620.34) — Employment cost not a “factor other than sex.”

A wage differential based on claimed differences between the average cost of employing workers of one sex as a group and the average cost of employing workers of the opposite sex as a group is discriminatory and does not qualify as a differential based on any “factor other than sex,” and will result in a violation of the equal pay provisions, if the equal pay standard otherwise applies.