In previous decades, researchers have identified a gender gap in the careers and academic achievement of men and women in science, technology, engineering, and mathematics (STEM). Recently, it has been suggested that some of these gender gaps no longer exist; however, the picture is more nuanced, for women are represented well in some STEM fields (such as biology) and not in others (such as computer science). The current research employed survey methodology to explore the perceptions of 360 finalists and semifinalists of the prestigious Science Talent Search. Two cohorts of participants who were either in their late 30s (Cohort 2) or late 20s (Cohort 1) were contacted to investigate factors that influenced them to select or not select STEM college majors and occupations. Comparisons between men and women revealed that women recalled having lower self-efficacy in STEM in college than men, and fewer women selected STEM majors as undergraduates. Interest was cited as a major influence for occupational selection for both men and women. Proportionally, more women than men entered fields such as biology and fewer women entered fields such as engineering and physics/astronomy. A greater proportion of older women mentioned leaving STEM because of a lack of flexible hours and needing to attend to family responsibilities. Implications for education and future research are discussed. (Contains 9 tables and 2 figures.)