Although opponents of genetic manuipulation frequently raise the specter of eugenics, our contemporary debates about bioethics often take place in a historical vacuum. In fact, American religious leaders raised similarly challenging ethical questions in the first half of the twentieth century. Preaching Eugenics tells how Protestant, Catholic, and Jewish leaders confronted and, in many cases, enthusiastically embraced eugenics - a movement that embodied progressive attitudes about modern science at the time. Christine Rosen argues that religious leaders pursued eugenics precisely when they moved away from traditional religious tenets. The liberals and modernists - those who challenged their churches to embrace modernity - became the eugenics movement's most enthusiastic supporters. Their participation played an important part in the success of the American eugenics movement. The story of how religious leaders confronted one of the era's newest "sciences," sheds important new light on a time much like our own, when religion and science are engaged in critical and sometimes bitter dialogue.