This study investigated changes between 1987 and 1996 in the proportions of ACT-tested students taking or planning to take high school mathematics and science courses prior to high school graduation. The changes in course-taking patterns among racial/ethnic and gender subgroups were also compared. The seven courses studied were Algebra II, Geometry, Trigonometry, Calculus, Other Advanced Mathematics, Chemistry, and Physics. In general, the percentages of students taking advanced mathematics and science courses increased for all racial/ethnic and gender groups. However, the increase was greater for females than for males; it was also greater for American Indians, Mexican Americans, and Blacks than for Other Hispanics, Asians, or Whites. Similarly, greater increases were observed in the average ACT Composite and ACT Mathematics scores of females, American Indians, Mexican Americans, and Blacks. In contrast, total group average ACT Composite and ACT Mathematics scores remained stable or increased only slightly. During the time period, the percentage of females and minority students in the ACT-tested population increased. Contains 25 references. (Author)