This study examines development along Perry's intellectual and ethical scale among three successive graduating classes of students identified as gifted and talented in mathematics and science. Perry posits that intellectual development proceeds from a basic dualism through nine stages ("positions") and culminates with a sense of personal identify and commitment. Perry suggests that the college years act as the agent of intellectual development, but others have argued that Perry's scheme is not flexible enough to account for gender- and culture-based differences. This study uses a paper-and-pencil questionnaire to describe developmental characteristics of gifted high school students and examines between-group differences between gender and ethnic groups at the high school sophomore and senior years. All groups showed significant improvement from sophomore to senior year. There were no differences by gender or ethnicity at the sophomore year, but by senior year, significant developmental differences existed among ethnic groups. (Contains 4 tables.)