"The discrepancy in course-taking between the males and the females taking the SAT occurs in courses that are normally electives following the geometry course. For example, 93 percent of both females and males reported taking a geometry course and 96 percent of males and females took algebra. There is a 3 percent difference in the proportion taking precalculus, however: 32 percent for females versus 35 percent for males. The gap increases to 4 percent for trigonometry (52 percent versus 56 percent) and there is a 5 percent difference in the proportion of high school students taking calculus (18 percent female versus 23 percent male)... , 97 percent of all students, both female and male, had taken biology, and 82 percent of both sexes had taken chemistry. Only 40 percent of females took physics, however, compared with 51 percent of males. In coursework intensiveness, only 7 percent of females took more than 4 years of natural science, compared with 9 percent of males."
-- Women, Minorities, and Persons with Disabilities in Science and Engineering 1994, NSF study.