In this exploratory study, students at a US university were asked about their motivations for enrolling or not enrolling in a human sexuality course. Questionnaires were given to 617 undergraduate students enrolled in a human sexuality course and to 169 final-year students who had not taken the course. The top five reasons students gave for enrolling were: (1) it seemed more interesting than other courses; (2) friends recommended it; (3) it met an academic requirement; (4) easy 'A'; and (5) other courses were full. The first reason for enrolling specific to desiring knowledge of sexuality was ranked sixth. Although the sexuality course has never limited enrolment, only a small percentage of undergraduates choose to take the course. The top five reasons that graduating seniors had not enrolled were: (1) could not work it into their schedule; (2) not interested; (3) not aware of the course; (4) already knew enough about sexuality; and (5) it did not fill a requirement. When some incongruent responses were eliminated, the primary reason for not enrolling was 'not interested.' The results indicate that sex educators should not assume that most college students want classroom-taught sexuality education. Suggestions are provided that may help increase interest.