Occupations are segregated by sex today, but were far more segregated in the early to mid-twentieth century. It is difficult to rationalize sex segregation and “wage discrimination” on the basis of men’s taste for distance from women in the same way differences between other groups in work and housing have been explained. Rather, this paper constructs a “pollution” theory model of discrimination in which occupations are defined by the level of a single-dimensional productivity characteristic. Because there is asymmetric information regarding the value of the characteristic of an individual woman, a new female hire may reduce the prestige of a previously all-male occupation. The predictions of the model include that occupations requiring a level of the characteristic above the female median will be segregated by sex and those below the median will be integrated. The historical record reveals numerous cases of the model’s predictions. For example in 1940 the greater is the productivity characteristic of an office and clerical occupation, the higher the occupational segregation by sex. “Credentialization” that spreads information about individual women’s productivities and shatters old stereotypes can help expunge “pollution.”
The converging roles of men and women are among the grandest advances in society and the economy in the last century. These aspects of the grand gender convergence are figurative chapters in a history of gender roles. But what must the “last” chapter contain for there to be equality in the labor market? The answer may come as a surprise. The solution does not (necessarily) have to involve government intervention and it need not make men more responsible in the home (although that wouldn’t hurt). But it must involve changes in the labor market, in particular how jobs are structured and remunerated to enhance temporal flexibility. The gender gap in pay would be considerably reduced and might vanish altogether if firms did not have an incentive to disproportionately reward individuals who labored long hours and worked particular hours. Such change has taken off in various sectors, such as technology, science and health, but is less apparent in the corporate, financial and legal worlds.