Despite the nonexistence of institutional obstacles, majors in science and mathematics continuously attract women to a greater extent than those in technology and engineering. Based on a series of in-depth interviews conducted with students of various STEM majors in an university and a polytechnic in the same city in Poland, this paper attempts to explore the reasons for this divergence. Analysis of the detailed biographical narrations reveals that the women’s choice of male-dominated majors coincides with the presence of a significant role model (SRM) in the close social network. An SRM is an individual who is more experienced in a given domain and who has personal, lasting, and emotional contact with the decision-maker. The presence of an SRM was observed most often among female students of polytechnic, and was hardly observable among their university counterparts. The SRM provided various forms of support and information, and debunked discouraging stereotypes of maledominated majors. Furthermore, a long-lasting relationship with the SRM led to the development of a strong preference for polytechnics over universities. Those findings fit well with the explanations provided by the theory of social contagion.