Technological innovations and social developments have led to dramatic changes in the practice of medicine and in the way that scientists conduct medical research. Change has brought beneficial consequences, yet these gains have come at a cost, for many modern medical practices raise troubling ethical questions: Should life be sustained mechanically when the brain's functions have ceased? Should potential parents be permitted to manipulate the genetic characteristics of their embryos? Should society ration medical care to control costs? Should fetal stem cells be experimented upon in an effort to eventually palliate or cure debilitating diseases? Bioethicists analyze and assess moral dilemmas raised by medical research and innovative treatments; they also counsel healthcare practitioners, patients, and their families. In this anthology, fifteen philosophers, social scientists, and academic lawyers assess various aspects of this field.