This paper explores the impact of the expansion in professional opportunities that American
women faced on teacher supply and teacher quality. Using standardized test scores, undergraduate
institution selectivity, and positive assortative mating characteristics as measures of quality, evidence of a
marked decline in the quality of young women going into teaching is documented. In contrast, the quality
of young women becoming professionals increased. The more teachers are paid relative to professionals,
the more likely educated women and blacks are to choose to teach. When wage opportunities in teaching
become relatively less attractive, the quality of teachers and prospective teachers declines. These effects
of relative earnings are economically significant.