The statistics show that the number of Computer Science majors is dropping across the United States. Possible reasons include a reduced number of jobs in the field, an incorrect perception of what Computer Scientists do, and the students’ disinterest due to a lack of familiarity with the subject. The reasons may be different for males and females. This paper reports on a study in which 836 high school calculus and pre-calculus students were surveyed to try to determine why students with an apparent aptitude for CS did not pursue a major in Computer Science. The results supported some of the hypotheses for declining enrollment, and rejected others. The top reasons for rejecting the major were the same for both genders, but the reasons for choosing the major differed. Categories and Subject Descriptors K.3.2 [Computers and Education]: Computer and Information Science Education - Computer Science Education, Curriculum, Literacy K.7.1[The Computing Profession]: Occupations General Terms...