Since the 1970s, the interrelated areas of medical genetics and biotechnology have developed dramatically and afforded increased control over the design of living organisms. From the very beginning, controversies over these techniques and their applications to plants, animals, and humans have raged in many disciplines--including science, philosophy, ethics, and religion. This book brings together the seminal essays of two leading Catholic moral theologians--Thomas Shannon and James Walter--in an effort to identify the key ethical and theological questions raised by the new genetic medicine. What is unique about this book is that it specifically and directly brings modern genetics and the Roman Catholic theological and ethical tradition into dialogue. While the authors argue that the Catholic tradition has much to offer in putting this current scientific revolution into perspective, they well understand the need to avoid merely repeating the tradition in favor of bringing the best of the tradition to bear on the precise questions posed by modern genetic technology.