Women in the United States are underrepresented in science, mathematics, and engineering (SME) educational programs and careers. One cause is the dramatic and disproportionate loss of women who intended in high school to pursue science-related careers. This article uses the longitudinal survey responses of 320 male and female SME summer program students to assess the ways in which their social relationships and experiences affect their involvement in science and technology. The issues are framed in terms of identity theory. Structural equation models support the identity framework; emotionally