Part I, The substantial identity thesis. 1. Why abortion is seriously wrong : two views / Donald Marquis - 2. Substantial identity, rational nature, and the right to life / Patrick Lee - Part II, Moral and legal issues at the beginning and ending of life. 3. Embryo ethics : justice and nascent human life / Robert P. George - 4. Compassion and the personalism of American jurisprudence : bioethical entailments / R. Mary Hayden Lemmons - 5. The significance of the ultimate end for the feeding of PVS patients : a reply to Kevin O'Rourke / Peter F. Ryan - Part III, Double effects and bioethics. 6. Praeter intentionem in Aquinas and issues in bioethics / E. Christian Brugger - 7. The action-omission and double effect distinctions / Timothy Chappell - Part IV, Bioethics and the natural law : challenges. 8. Global bioethics and natural law / Ana S. Iltis - 9. Guided autonomy and good friend physicians / Janet Smith - Part V, The right to health care. 10. Social justice, charity and tax evasion : a critical inquiry / Mark J. Cherry - 11. Natural law, property, and welfare rights / Andrew Lustig - 12. Health care technology and justice / Germain Grisez - Part VI, Boyle responds. 13. An appreciative response / Joseph M. Boyle