The scientific, ethical, and policy issues raised by research involving the engraftment of human neural stem cells into the brains of nonhuman primates are explored by an interdisciplinary working group in this Policy Forum. The authors consider the possibility that this research might alter the cognitive capacities of recipient great apes and monkeys, with potential significance for their moral status.

: Experiments involving the transplantation of human stem cells and their derivatives into early fetal or embryonic nonhuman animals raise novel ethical issues due to their possible implications for enhancing the moral status of the chimeric individual. Although status-enhancing research is not necessarily objectionable from the perspective of the chimeric individual, there are grounds for objecting to it in the conditions in which it is likely to occur. Translating this ethical conclusion into a policy recommendation, however, is complicated by the (...) fact that substantial empirical and ethical uncertainties remain about which transplants, if any, would significantly enhance the chimeric individual's moral status. Considerations of moral status justify either an early-termination policy on chimeric embryos, or, in the absence of such a policy, restrictions on the introduction of pluripotent human stem cells into early-stage developing animals, pending the resolution of those uncertainties. (shrink)

: The transplantation of adult human neural stem cells into prenatal non-humans offers an avenue for studying human neural cell development without direct use of human embryos. However, such experiments raise significant ethical concerns about mixing human and nonhuman materials in ways that could result in the development of human-nonhuman chimeras. This paper examines four arguments against such research, the moral taboo, species integrity, "unnaturalness," and human dignity arguments, and finds the last plausible. It argues that the transfer of human (...) brain or retinal stem cells to nonhuman embryos would not result in the development of human-nonhuman chimeras that denigrate human dignity, provided such stem cells are dissociated. The article provides guidelines that set ethical boundaries for conducting such research that are consonant with the requirements of human dignity. (shrink)

Euthanasia, today, is one of the most debated issues in bioethics. Euthanasia, at the time of Thomas Aquinas, was an unheard-of term. Nevertheless, while there is no direct statement with respect to “euthanasia” per se in the writings of Aquinas, Aquinas’s moral theory and certain theological commitments he held could be applied to the euthanasia question and thus bring Aquinas into contemporary bioethical debate. In this paper, I present the relevant aspects of Aquinas’s account of natural law and his theological (...) views on suffering, examining what conclusions each entails with respect to directly intended euthanasia. I then proceed to discuss cases that involve either the administration of palliative medication that hastens death, terminal sedation, or the non-utilization of life-sustaining treatment. This involves a detailed investigation into Aquinas’s account of human intentional action and the question of whether Aquinas holds some form of the Principle of Double-Effect. I end with a final statement of Aquinas’s position on these various types of cases as a synthesis of the conclusions drawn from the different areas of his thought discussed in this paper. My aim is to provide a set of guidelines, based upon Aquinas’s thought, for those who may be faced with decisions regarding the proper form of palliative treatment to be provided to those suffering from a painful terminal illness. Decision-makers, in such cases, may include a terminally ill patient, a patient’s immediate family, health care providers, and lawmakers concerned with establishing the legality of certain forms of treatment. Establishing a clear set of moral guidelines, specifically addressed to this type of decision, can assist the relevant decision-makers in forming their consciences such that they may take the appropriate course of action in confronting the suffering of a terminally ill patient. (shrink)

In addressing bioethical issues at the beginning of human life, such as abortion, in vitro fertilization, and embryonic stem cell research, one primary concern regards establishing when a developing human embryo or fetus can be considered a person. Thomas Aquinas argues that an embryo or fetus is not a human person until its body is informed by a rational soul. Aquinas's explicit account of human embryogenesis has been generally rejected by contemporary scholars due to its dependence upon medieval biological data, (...) which has been far surpassed by current scientific research. A number of scholars, however, have attempted to combine Aquinas's basic metaphysical account of human nature with current embryological data to develop a contemporary Thomistic account of a human person's beginning. In this article, I discuss two recent interpretations in which it is argued that a human person does not begin to exist until a fetus has developed a functioning cerebral cortex. (shrink)