"Rethinking the Moral Permissibility of Gamete Donation," Theoretical Medicine and Bioethics 35, 6 (2014) 421-440

“Natural Law, Parental Rights and Education Policy," American Journal of Jurisprudence (December 2014)

"Social Contract Theory and Moral Agency: Understanding the Roots of an Uncaring Society," in Caring Professions and Globalization: Philosophical and Practical Perspectives, ed. Ana Marta Gonzalez and Craig Iffland, Palgrave MacMillan, 2014, p. 87-116

"Natural Law" (co-authored with Robert George), International Encyclopedia of Social and Behavioral Sciences, Second Edition

"Personal Identity and Gender: A Revised Aristotelian Approach," in Gender Identities in a Globalized World, ed. Ana Marta Gonzalez and Victor Seidler, Humanity Books, 2008, p. 75-108