Too often women encounter the argument that pay disparity is the outcome of market forces and not sex discrimination. Salary differentials are attributed to individual pay demands, bargaining effectiveness, external counteroffers and/or prior salaries. These are just a few examples of market justifications employers raise to explain why similar workers performing the same job are compensated differently. This paper argues that, in most cases, market justifications for pay disparity in equal pay for equal work litigation should be rejected. The paper then takes on the more ambitious project of proposing an alternative model of gender discrimination, which is not restricted to causation. Anti-discrimination mandates outlaw employment practices that discriminate against women because of their sex. I argue that in the limited case of equal pay litigation, we should abandon this causation requirement. In Equal Pay Act (EPA) claims, an alternative model of equality should be endorsed, which would restrict the employer’s ability to defend differential wages for equal work to cases where he can present evidence that individual ability or productivity considerations support the disputed pay disparity. The gender wage gap is a complex phenomenon. There are at least three causation issues which remain unsettled in the literature discussing the gender wage gap. First, disagreement surrounds the identification of the variables responsible for the wage gap. Second, the relative significance of various contributing factors is disputed. Third, the underlying relationship between some factors and past and present societal discrimination is also often questioned. In this climate of empirical uncertainty adhering to a definition of discrimination which requires the plaintiff to articulate causality between the employer’s seemingly neutral and market guided compensation policies and sex, will frustrate most claims of pay discrimination. Broad interpretation of what constitutes a valid defense may undermine the EPA’s goal of eliminating unjustified wage disparities. Some defenses, especially variants of the market force defense, are actually discriminatory practices since they disadvantage women as a group. The opportunity to interpret the EPA as restricting employer discretion to pay employees of opposite sexes disparate compensation to a checklist of authorized factors relating to productivity and ability was overlooked by the courts. Currently EPA jurisprudence is under-theorized. In a series of decisions the courts interpreted the EPA to emulate Title VII of the Civil Rights Act (1967) models of discrimination which are based on strong causation. This enabled employers to make use of the market defense to severe the causal link between sex and compensation. But in January 2009, Congress passed H.R. 12, The Paycheck Fairness Act. This bill, amending the EPA, clarifies that the scope of the employer’s affirmative defense is quite narrow, and in fact is limited to considerations closely related to individual ability and productivity. If this important legislation becomes law, the market defense will be eliminated altogether from the EPA framework of discrimination.