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, iscomplicated 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)

Transhumanism is the school of thought that advocates the use of technology to enhance the human species, to the point where some supporters consider that a new species altogether could arise. Even some critics think this at least a technological possibility. Some supporters also believe the emergence of a new, improved, superhuman species raises no special ethical questions. Through an examination of the metaphysics of species, and an analysis of the essence of the human species, I argue that the existence (...) of an embodied, genuinely superhuman species is a metaphysical impossibility. Finally, I point out an interesting ethical consideration that this metaphysical truth raises. (shrink)

Recent developments in biotechnology and genetic research are raising complex ethical questions concerning the legitimate scope and limits of genetic intervention. As we begin to contemplate the possibility of intervening in the human genome to prevent diseases, we cannot help but feel that the human species might soon be able to take its biological evolution in its own hands. 'Playing God' is the metaphor commonly used for this self-transformation of the species, which, it seems, might soon be within our grasp. (...) In this important new book, Jurgen Habermas - the most influential philosopher and social thinker in Germany today - takes up the question of genetic engineering and its ethical implications and subjects it to careful philosophical scrutiny. His analysis is guided by the view that genetic manipulation is bound up with the identity and self-understanding of the species. We cannot rule out the possibility that knowledge of one's own hereditary factors may prove to be restrictive for the choice of an individual's way of life and may undermine the symmetrical relations between free and equal human beings. In the concluding chapter - which was delivered as a lecture on receiving the Peace Prize of the German Book Trade for 2001 - Habermas broadens the discussion to examine the tension between science and religion in the modern world, a tension which exploded, with such tragic violence, on September 11th. (shrink)

Human–nonhuman chimeras have been the focus of ethical controversies for more than a decade, yet some related issues remain unaddressed. For example, little has been said about the relationship between the origin of transferred cells and the morally relevant capacities to which they may give rise. Consider, for example, a developing mouse fetus that receives a brain stem cell transplant from a human and another that receives a brain stem cell transplant from a dolphin. If both chimeras acquire morally relevant (...) capacities as a result of transplantation, and if those capacities are indistinguishable, should the difference in cell origin matter to how we classify these creatures? I argue that if morally relevant capacities are easy to detect, cell origin is irrelevant to how the chimera ought to be treated. However, if such capacities are hard to detect, cell origin should play a role in considerations about how to treat the chimera. (shrink)

This paper addresses several questions related to the nature, production, and use of animal-human (a-h) chimeras. At the heart of the issue is whether certain types of a-h chimeras should be brought into existence, and, if they are, how we should treat such creatures. In our current research environment, we recognize a dichotomy between research involving nonhuman animal subjects and research involving human subjects, and the classification of a research protocol into one of these categories will trigger different ethical standards (...) as to the moral permissibility of the research in question. Are a-h chimeras entitled to the more restrictive and protective ethical standards applied to human research subjects? We elucidate an Aristotelian-Thomistic metaphysical framework in which to argue how such chimeras ought to be defined ontologically. We then examine when the creation of, and experimentation upon, certain types of a-h chimeras may be morally permissible. (shrink)

The creation of chimeras by introducing human stem cells into nonhu- man animals has provoked intense concerns. Addressing objections that appeal to human dignity, I focus in this essay on stem cell research intended to generate human neurons in Great Apes and rodents. After considering samples of dignity- based objections from the literature, I examine the underlying assumption that nonhuman animals have lower moral status than personsFwith particular attention to what it means to speak of higher and lower moral statusFbefore (...) evaluating the chimera research in question. I argue that (1) such experiments involving Great Apes should be prohibited out of respect for the research subjects and (2) such experiments involving rodents may or may not be permissible, depending on how we answer unresolved questions regarding rodents’ moral status. In the end, concerns about human dignity prove insignificant. (shrink)

In January 2008, the Human Fertilisation and Embryology Authority issued two 1-year licenses for cytoplasmic hybrid embryo research. This article situates the HFEA's decision in its wider scientific and political context in which, until quite recently, the debate about human embryonic stem cell research has focused narrowly on the moral status of the developing human embryo. Next, ethical arguments against crossing species boundaries with humans are canvassed. Finally, a new argument about the risks of harm to women egg providers resulting (...) from research involving the creation of humanesque cytoplasmic hybrid embryos is elaborated. Taken together these ethical concerns about the moral status of the human embryo, about the ethics of crossing species boundaries with humans, and about the potential harms to women, provide good reason to eschew humanesque cytoplasmic hybrid embryo research in favor of less ethically controversial means to the laudable end of successful regenerative medicine. (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)

Discussions about whether new biomedical technologies threaten or violate human dignity are now common. Indeed, appeals to human dignity have played a central role in national and international debates about whether to allow particular kinds of biomedical investigations. The focus of this paper is on chimera research. I argue here that both those who claim that particular types of human-nonhuman chimera research threaten human dignity and those who argue that such threat does not exist fail to make their case. I (...) first introduce some of the arguments that have been offered supporting the claim that the creation of certain sorts of chimeras threatens or violates human dignity. I next present opponents' assessments of such arguments. Finally I critically analyze both the critics' and the supporters' claims about whether chimera research threatens human dignity. (shrink)

Moral status is the moral value that something has in its own right, independently of the interests or concerns of others. Research using human embryonic stem cells implicates issues about moral status because the current method of extracting hESCs involves the destruction of a human embryo, the moral status of which is contested. Moral status issues can also arise, however, when hESCs are transplanted into embryonic or fetal animals, thereby creating human/ nonhuman stem cell chimeras. In particular, one concern about (...) chimera research is that it could confer upon an animal the moral status of a normal human adult, but then impermissibly fail to accord the animal the protections it merits in virtue of its enhanced status. Understanding the public policy implications of this ethical conclusion is complicated by the fact that certain views about the moral status of the embryo cannot legitimately be used to justify public policy decisions. Arguments like those employed in the abortion debate for the conclusion that abortion should be legally permissible even if abortion is not morally permissible also support, to a more limited degree, a liberal policy on hESC research involving the creation of chimeras. (shrink)

Research that involves the creation of animals with human-derived parts opens the door to potentially valuable scientific and therapeutic advances, yet invokes unsettling moral questions. Critics and champions alike stand to gain from clear identification and careful consideration of the strongest ethical objections to this research. A prevailing objection argues that crossing the human/nonhuman species boundary introduces inexorable moral confusion (IMC) that warrants a restriction to this research on precautionary grounds. Though this objection may capture the intuitions of many who (...) find this research unsettling, it relies on mistaken views of both biology and moral standing, ultimately distorting the morally relevant facts. We critically examine IMC, identify mistaken essentialist assumptions, and reframe ethical concerns. The upshot is a stronger line of objection that encourages a more inclusive and productive ethical discourse. (shrink)

This paper critically examines the biology of species identity and the morality of crossing species boundaries in the context of emerging research that involves combining human and nonhuman animals at the genetic or cellular level. We begin with the notion of species identity, particularly focusing on the ostensible fixity of species boundaries, and we explore the general biological and philosophical problem of defining species. Against this backdrop, we survey and criticize earlier attempts to forbid crossing species boundaries in the creation (...) of novel beings. We do not attempt to establish the immorality of crossing species boundaries, but we conclude with some thoughts about such crossings, alluding to the notion of moral confusion regarding social and ethical obligations to novel interspecies beings. (shrink)

The controversy over the creation of admixed human- nonhuman embryos, and specifically of what have been termed “cybrids,” involves a range of ethical and political issues. It is not reducible to a single question. This paper focuses on one question raised by that controversy, whether creating admixed human-nonhuman entities is “an offense against human dignity.” In the last decade there has been sustained criticism of the use of the concept of human dignity within bioethics. The concept has been criticized as (...) “vague” and “useless.” Nevertheless, the concept continues to be invoked in bioethical discussion and in international instruments. This paper defends a concept of human dignity that is coherent but that is wider than contemporary post- Kantian approaches. “Human dignity” is best regarded as having a set of analogically related meanings, more than one of which is relevant to the field of bioethics. A more subtle understanding of the concept of human dignity can hel identify what is ethically problematic in human-nonhuman combinations and so shed light on one aspect of the admixed embryo debate. (shrink)