Occupational segregation by sex occurs everywhere, causing labour mark
et rigidity and economic inefficiency, wasting human resources, preven
ting change, disadvantaging women and perpetuating gender inequalities
. The author reviews the principal theoretical explanations for its ex
istence and persistence: neo-classical and human capital; institutiona
l and labour market segmentation; and gender discrimination. Its compl
ex relationship with female-male pay differentials is also explored. T
hough all prove pertinent, the most compelling explanations of occupat
ional segregation by sex are gender theories, given the enormous overl
ap in abilities and preferences of individual men and women.