(Same as Clusters M72B, Society and Genetics M72B, and Sociology M72B.) Lecture, three hours; discussion, two hours. Enforced requisite: course M72A. Limited to first-year freshmen. Examination of many ways in which sex and sexual identity shape and are shaped by biological and social forces, approached from complementary perspectives of anthropology, biology, medicine, and sociology. Specific topics include biological origins of sex differences, intersex, gender identity, gender inequality, homosexuality, sex differences, sex/gender and law, and politics of sex research. Letter grading.