These points contribute to the frightening scenario she constructs, and they display an ambivalence toward medical technology that is far from new. Worries, calls for bans, and hostility have become part and parcel of Western responses to genetic engineering, in vitro fertilization, embryo research, and cloning. [20]

Those who oppose or seek to delimit new medical technologies often appeal to nature as morally normative. Persons who respect natural boundaries are considered ethical, while those who seek to change normal biological functioning are considered disrespectful and immoral. Appeals to the natural as moral and to the unnatural as immoral are especially strong when medical technologies are new, strange, or, to use one of Clark's terms, "disgusting." [21] The history of modern medicine illustrates how those who were alarmed over anesthesia, invasive surgery, contraceptive measures, heart transplants, and the innovative medical technologies just listed turned to nature as normative. In part, what seems natural or unnatural is a function of familiarity. [22]

Beyond familiarity, moral assumptions that are predicated on the natural as normative are part of a long tradition of ethical reflection based on natural law. [23] Insofar as it is predicated on nonreligious assumptions, the view that ethical norms can be derived from natural biological functions is fraught with difficulties. Although most natural law approaches appeal to human nature -- especially human rationality and relationships -- the view that nature's functions can serve as a basis for human morality offers a "totally inadequate conception of the nature of human beings."[24] It assumes that all we humans can and should do ethically is to discover, then to conform with biological functions inherent to nature. Furthermore, this view undercuts science, engineering, and particularly medicine, because all these manipulate nature toward human ends.

This version of natural law ethics has also been predicated on the religious view that humans should not unduly tamper with God's creation. It would be interesting to know the degrees to which this view might have influenced the respective history and current content of European and U.S. patent law. That aside, it is notable that, due to their shared belief concerning the supreme value of preserving human life, Judaism, Catholicism, Protestantism, and Islam offer no principled objections to animal-to-human transplants. [25]

[18.] See Clark, supra note 1, at 148. [M.A. Clark, "This Little Piggy Went to Market: The Xenotransplantation and Xenozoonose Debate," Journal of Law, Medicine & Ethics, 27 (1999): 137-52.]

[19.] See id. at 144.

[20.] See R.M. Zaner, "Surprise! You're Just Like Me?: Reflections on Cloning, Eugenics, and Other Utopias," in J.M. Humber and R.F. Almeder, eds., Human Cloning (Totowa: Humana Press, 1998): 105-51.

[21.] See Clark, supra note 1, at 141.

[22.] See A.L. Caplan, "Is Xenografting Morally Wrong?," Transplantation Proceedings, 24 (1992): 722-27.

[23.] See S. Buckle, "Natural Law," in P. Singer, ed., A Companion to Ethics (Oxford: Basil Blackwell, 1993): 161-74. 24. Id. at 172.

[25.] See Nuffield Council on Bioethics, supra note 16; and R.M. Veatch, "The Ethics of Xenografts," Transplantation Proceedings, 3 (1986): 93-97.