The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Macpherson and Hirsch (1995) of the effects of occupational gender composition on earnings using monthly CPS data for 1973-1993. In the updating process, we correct for biases in this dataset due to the inclusion of imputed earners and the misreporting of occupation. CPS data for 1996-2010 are used to provide cross-sectional estimates of the impact of feminization on wages as well as its contribution to the gender wage gap. Longitudinal CPS data indicates that the negative effects of gender composition on earnings observed in cross section are lessened (much reduced) when we control for observed (unobserved) heterogeneity. These findings are confirmed using much longer panels from the NLSY. Finally, constructing synthetic panels of aging cohorts suggests that wage penalties are largest for younger cohorts in female occupations. (134 words) JEL Classification: J31, J71 Keywords: wages, gender composition, gender wage gap At first blush, the negative effect of the gender composition of an occupation -that is, its proportion female -on the earnings of women (and men) in that occupation might seem to offer a blueprint for policy initiatives. Such measures might include quotas to increase the female component in male jobs and comparable worth, together with more conventional instruments seeking to strengthen human capital endowments. Unfortunately, the empirical consensus does not extend much beyond agreement on the stylized facts of earnings disparities that are increasing in feminization. Acting to blunt policy activism, therefore, is disputation as regards the size and persistence of the negative correlation between gender composition and wages as well as disagreement as to underlying causation.At root, the controversy has a basis in a literature often containing scant controls for observables such as occupational characteristics that may influence earnings and earning development. Further, the number of studies using longitudinal analysis is still somewhat meager. In the latter context the gender composition variable may in practice be correlated with unmeasured skill and taste differences among workers, and in the former with controls for occupational attributes that might reasonably be expected to influence earnings.The present paper is motivated by an important study of occupational sex segregation by Macpherson and Hirsch (1995) that is notable in three principal respects: first, in its use of several large datasets; second, in its deployment of arguments not typically found in...