This dissertation seeks to expand and refine our understanding of sex-segregation in the labor market. The rapid changes in women’s roles that have taken place in recent decades have made traditional explanations incapable of accounting for current patterns of mobility in the labor market, and the persistence of sex-segregation in modern times. Throughout this dissertation I draw on a wide variety of sources and research methods to examine the striking movement of women out of male-dominated occupations in the U.S. There is an important conundrum to unravel, as less attrition of women from male-dominated occupations would mean more progress was being made toward the integration of men and women in the workplace. Results indicate the emergence of new line of demarcation between women; whereas a minority of women tend to plan their job careers more efficiently in a similar way to men, low-status women continue to have unstructured career patterns.