Leon R. Kass, MD, is the Addie Clark Harding Professor Emeritus in the Committee on Social Thought and the College at the University of Chicago and Hertog Fellow in Social Thought at the American Enterprise Institute. A member of the President’s Council on Bioethics, he is the author or coauthor of five books, including, most recently, Life, Liberty and the Defense of Dignity: The Challenge for Bioethics.