Concern over the underrepresentation of women and minorities in the natural sciences and engineering led to the research reported here. This project surveyed a stratified sample of 1,651 college seniors who registered to take the Graduate Record Examinations (GRE) General Test in December 1990 and who were majoring in natural sciences, mathematics, computer sciences, and engineering (NSME). The sample was stratified to contain all minorities and approximately equal numbers of White male and female U.S. citizens majoring in these fields. All were taking the GRE in the process of applying to graduate school. The goals of the survey were threefold: (1) to identify some of the factors that may lead NSME majors to change fields for graduate school, that is, to leave the science/engineering pipeline directly after earning a bachelor's degree; (2) to analyze differences among ethnic groups remaining in NSME; and (3) to analyze differences between male and female NSME majors who plan to remain in NSME. Results of the first goal of the survey were reported earlier; this report focuses on the second and third goals of the study --gender and ethnic differences in NSME majors planning graduate study in their fields. Results showed that the decision to leave NSME was uncorrelated with gender, race, or GRE scores, but was correlated with many questionnaire items. Detailed analyses of gender and ethnic differences among NSME majors planning to continue in their fields showed small to moderate differences on many dimensions, including grades, GRE scores, mother's education and occupation, out-of-class activities, degree objective, ability to perceive oneself as a scientist or engineer, perception of professionals in their field, perception of faculty, interaction with faculty, regard for other students in the department, and belief that they could make a real contribution in their field. Differences in undergraduate experiences included opportunities to assist professors in their research, ratings of teaching methods and evaluation procedures, intellectual environment, and the variety of advanced course offerings. Gender and ethnic differences also appeared in a number of self-ratings.