Abstract
How are males and females different? Most people have a sex that is consistent on all levels: genetic, gonadal, internal genitals, external genitals. But sometimes there are discrepancies. This case explores the biology of human sexual differentiation and its social and ethical ramifications. In working through the case, students will also learn how scientists use laboratory experiments on animals and "experiments of nature," or conditions that occur naturally in humans, to help them understand human biology. The case is modular to the extent that not all parts must be used. The case has been taught by the authors in a variety of courses including genetics, physiology, and a core curriculum science course for non-majors.