"In 1954, researchers at the newly formed National Institute of Mental Health set out to study the genetics of schizophrenia. When they got word that four 24-year-old identical quadruplets in Lansing, Michigan, had all been diagnosed with the mental illness, they could hardly believe their ears. Here was incontrovertible proof of hereditary transmission and, thus, a chance to bring international fame to their fledgling institution. The case of the...