This study examined young students' perceptions of gender-appropriate science courses. The sample consisted of 427 students in grades 4, 5, and 6, between the ages of 9 and 13. Students completed the Course Selection Sheet (CSS) to choose courses for themselves and members of the opposite gender. A psychosocial framework was offered to explain the differential course selection patterns between young boys and girls. The study reveals a strong gender effect pointing toward stereotypical perceptions of selected science courses for oneself (p ≤ 0.01). When students selected science courses for the opposite gender, the evidence of gender-role stereotypes was even greater (p < 0.000). Course selection profiles imply that a reciprocal relationship exists in the number and kind of courses selected by girls and boys. A detailed analysis suggests that both boys and girls perceive physical science and technology-related courses as appropriate subjects for boys to study and life sciences as appropriate subjects for girls to study. Surprisingly, students' future science course selections resemble current enrollment data of master's and doctoral candidates. The students' perceptions of science are seen years prior to the actual encounter with the science courses listed on the course selection menu. These findings question the auspiciousness of programs designed to ameliorate gender differences in science during junior or senior high school years. Suggestions for school curriculum development and the importance of informal science experiences were examined. © 1999 John Wiley & Sons, Inc. Sci Ed 83:55–75, 1999.