Compared were gender differences among Asian and Caucasian high school students enrolled in advanced science and mathematics research classes. Two explanations for the large gender differences among scientists, mathematicians, and engineers are discussed: (1) females elect fewer advanced science and mathematics courses in high school and college, and are thus prevented from entering technical-scientific fields; and (2) large sex differences exist in specific innate abilities. It is held that should the latter be true, then these gender differences would appear among all ethnic groupings. If, however, these differences disappear, then the achievement differences might be related to different socialization patterns. Using this premise, the study involved 27 high schools with atypical numbers of Asians and/or females enrolled in advanced science and mathematics courses. A questionnaire was given to 209 Caucasian and 78 Asian students, followed by interviews with 39 students. Asian students devoted much more time to studying and research activities, with their families very supportive of such dedication, for both sexes. Asian students tended to retain the attitudes and values of their former countries, were more influenced by peers and others to achieve, and were more competitive than Caucasian students. Asian females read more technical books and knew more computer languages, while Caucasian females emphasized socialization. Both sets of females tended to have lower positive attitudes toward themselves. The Asian males as a group had very few negative stereotypes of the gifted girls in their classes, while American males had many negative perceptions of gifted females in their classes. Implications of the differences are commented upon. (MNS)