Gender: In the Genes or in the Jeans?
A Case Study on Sexual Differentiation
California State University Fullerton
Department of Math and Science
University of Maine at Presque Isle
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.
- To learn about the difference between autosomes and sex chromosomes.
- To learn about human sexual differentiation at the chromosomal, hormonal, phenotypic, brain, behavioral, and legal levels.
- To understand how scientists reached their understanding of these biological matters by considering both laboratory experiments on animals and "experiments of nature," or conditions that occur naturally in humans.
- To consider some ethical issues related to unusual chromosomal, gonadal, and genital conditions, including the individual's right to know, the roles of parents and physicians in deciding what's best for the child, and society's attitude towards these individuals.
- To gain experience in scientific reasoning, including making predictions based on alternative hypotheses, designing experiments, and interpreting results.
KeywordsGender; chromosomal sex; gonadal differentiation; Mullerian ducts; Wolffian ducts; testosterone; genital differentiation ; AIS; karyotyping; steroid hormones; sexual characteristics
Topical AreasSocial issues
Educational LevelHigh school, Undergraduate lower division
Type / MethodsDirected, Discussion, Interrupted
Subject HeadingsBiology (General) | Developmental Biology | Genetics / Heredity |
This case includes an optional PowerPoint presentation (file below) covering the topic of genital differentiation (details provided in Teaching Notes).
PPT on Differentiation