As a labor economist, my usual role in a discussion of women in the information technology (IT) workforce would be to establish the prevalence of gender differentials in outcomes. Elsewhere in this article, I address the question: Are women who invest time and money to acquire education and training in IT fields able to use their skills, and receive commensurate compensation, in the labor market? Because the answer to this question is simply “yes,” I explore a second question in this article: Given that women with computer science and engineering college majors earn far more (on average) than other college-educated women, why do so few choose to pursue this career path? The answer to this question matters both because we continue to puzzle about why women tend to earn less than men and because (as argued so eloquently by Margolis & Fisher, 2002) the kinds of technologies that will be developed will depend on the life experiences and interests of our highly-trained IT professionals. I approach this research by focusing on the college major choices of young women. While it is possible to enter IT careers through many different avenues, both occupational assignments and provision of on-the-job training result from complex interactions between individual workers and employers. In contrast, college major choices are typically far more unilateral, and tend to precede labor market entry. In my research, comparisons are made between women who choose to major in computer science or engineering and those who make other college major choices. While it is true that women in computer science or engineering fields tend to earn less than men with the same college major, gender differentials in earnings are a fact of life along other career paths as well. For example, in the most recent year for which detailed information is available, the gender differential in earnings among college graduates in their 30s ranged from 15% to 20% in each of four other broad college major categories2, compared to only 5% among both computer science and engineering majors (Weinberger & Joy, 2006).3 The information most relevant to women making their career choices is how the earnings of women in IT careers compare to the earnings of other women. On this measure, college training in IT fields appears to be a sound investment: Women with computer science or engineering majors tend to earn 30%-50% more than otherwise similar female college graduates (Weinberger, in this volume).4 The economic incentive for women to pursue these careers appears to be quite large. Based on this evidence, the barrier to women’s entry is evidently not a lack of lucrative career opportunities. Yet some kind of barrier clearly exists. Statistics available from the National Center for Education Statistics reveal that while the representation of women is now substantial among new college graduates in many previously male dominated fields, this is not true in either computer science or engineering fields.5 In 1970, fewer than 10% of new bachelor’s degree graduates in business, computer science, engineering or newly graduating doctors and lawyers, were women. Today, women and men are nearly equally represented among new graduates in business, law and medicine. In contrast, fewer than one-third of new computer science graduates, and an even smaller proportion of new engineers, are women. And there has been no obvious trend towards increasing representation of women in these fields in recent years. The research presented in the remainder of this article describes a survey of academically talented young women, asking questions designed to reveal what the operative barriers might be.