Recent advances in mapping the human genome suggest a vision of the future that might fill us with equal parts hope and dread. On the one hand, the possibility of identifying disease-causing genes may enable us to eradicate cancer, obesity, or depression before they ever develop. On the other hand, the idea that soon we could be “designing” our progeny, choosing physical and psychological traits we deem desirable, is fraught with deep moral complexities. But are these ideas realistic or just the stuff of science fiction? What real ethical problems does the current state of human genomics present? John and Ken map out the terrain with David Magnus, Director of the Stanford Center for Biomedical Ethics and co-editor of Who Owns Life?