Genetics in the Madhouse: The Unknown History of Human Heredity by Theodore M. Porter

In the early 1800s, a century before there was any concept of the gene, physicians in insane asylums began to record causes of madness in their admission books.  Almost from the beginning, they pointed to heredity as the most important of these causes.  As doctors and state officials steadily lost faith in the capacity of asylum care, they began emphasizing the need to curb the reproduction of the insane.  They became obsessed with identifying weak and tainted families and anticipating the outcomes of their marriages.  Genetics in the Madhouse is the story of how the collection and sorting of hereditary data in mental hospitals, schools for feebleminded children, and prisons gave rise to a new science of human heredity.