Earlier studies of gender differences in science courses and careers have identified three probable causes: numbers of mathematics courses, level of science achievement, and attitudes toward science. Recently, differential science experiences have been suggested as a factor contributing to the gender differences found in science interest and achievement. A study of science activities, both within and outside of school, has been conducted. Although both boys and girls report similar classroom experiences, boys more often than girls report extracurricular science activities. The findings suggest that equal experiences within science classrooms do not overcome the advantage that boys hold due to more extracurricular science activities. Increased experiences in science, however, have led to more positive attitudes toward science among the girls in this study.