The Cousin Marriage Debate

Culture & Identity

The Cousin Marriage Debate and the World of Science and Medicine in 19th-Century America

Ask Americans today why people no longer marry their cousins, and their answers usually reference genetics and scientific progress. Scientific discoveries, so the story goes, made evident the disastrous effects caused by cousin marriage—genetic diseases and monstrous deformities. Yet, the intense debates about cousin marriage that unfolded over the 19th century took place in a scientific and medical world that preceded the “rediscovery” of Mendelian principles of inheritance (and the invention of the very term “genetics”) and the development of a specific-germ theory of disease.

Anthropologist Susan McKinnon explores how a very different cultural logic of heredity and disease informed the debates about cousin marriage in the 19th century and considers what else was being talked about through the metaphors of heredity, breeding, health, and disease. It turns out that the debate was as much about these issues as it was also about the value of and conditions for scientific and medical authority, evolutionary progress, social equality, and a democratic Republic.