Animal models of human diseases are often used in biomedical research in place of human subjects. However, results obtained by animal models may fail to hold true for humans. One way of addressing this problem is to make animal models more similar to humans by placing human tissue into animal models, rendering them chimeric. Since technical and ethical limitations make neurological disorders difficult to study in humans, chimeric models with human neural tissue could help advance our understanding of neuropathophysiology. In (...) this article, we examine whether the introduction of human neural tissue and any consequent cognitive change is relevant to the way we ought to treat chimeras. We argue that changes in cognitive abilities are morally relevant to the extent that they increase the capacities that affect the moral status of any entity, including awareness, autonomy, and sociability. We posit that no being, regardless of species, should be treated in a way that is incommensurate with its moral status. Finally, we propose a framework that can be used to guide ethical assessment of research involving chimeras with advanced cognitive capacities. We advance this framework as a useful tool for bringing relevant considerations to the forefront for those considering the ethical merit of proposed chimeric research. In doing so, we examine concepts relevant to the question of how any entity may be treated, including moral status, dignity, and capacities. (shrink)

The burgeoning field of biomedical research involving the mixture of human and animal materials has attracted significant ethical controversy. Due to the many dimensions of potential ethical conflict involved in this type of research, and the wide variety of research projects under discussion, it is difficult to obtain an overview of the ethical debate. This paper attempts to remedy this by providing a systematic review of ethical reasons in academic publications on human-animal chimera research. We conducted a systematic review of (...) the ethical literature concerning human-animal chimeras based on the research question: “What ethical reasons have been given for or against conducting human-animal chimera research, and how have these reasons been treated in the ongoing debate?” Our search extends until the end of the year 2017, including MEDLINE, Embase, PhilPapers and EthxWeb databases, restricted to peer-reviewed journal publications in English. Papers containing ethical reasons were analyzed, and the reasons were coded according to whether they were endorsed, mentioned or rejected. Four hundred and thirty-one articles were retrieved by our search, and 88 were ultimately included and analyzed. Within these articles, we found 464 passages containing reasons for and against conducting human-animal chimera research. We classified these reasons into five categories and, within these, identified 12 broad and 31 narrow reason types.15% of the retrieved passages contained reasons in favor of conducting chimera research, while 85% of the passages contained reasons against it. The reasons against conducting chimera research fell into four further categories: reasons concerning the creation of a chimera, its treatment, reasons referring to metaphysical or social issues resulting from its existence and to potential downstream effects of chimera research. A significant proportion of identified passages fell under Category C. We hope that our results, in revealing the conceptual and argumentative structure of the debate and highlighting some its most notable tendencies and prominent positions, will facilitate continued discussion and provide a basis for the development of relevant policy and legislation. (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)

What types of human-animal interspecific entities are used in biomedical research? Is creating such entities morally wrong? And what do interspecifics tell us about the moral significance of species? This thesis offers an introduction to the field of human-animal interspecifics from a bioethical perspective, with a special focus on the question of speciesism.

Genetic engineering often generates fear of out of control scientists creating Frankenstein creatures that will terrorize the general populace, especially in the cases of human-animal chimeras. While sometimes an accurate characterization of some researchers, this belief is often the result of repugnance for new technology rather than being rationally justified. To facilitate thoughtful discussion the moral issues raised by human-animal chimeras, ethicists and other stakeholders must develop a rational ethical framework before raw emotion has a chance of becoming the dominating (...) justification for public opinion and policy. Derek Parfit’s work on lives worth living for human beings can provide valuable insight into the morality of creating chimeras. As long as their lives are overall good, then bringing them into existence does not harm them even if they are used for medical research or procedures, or they are created to carry on the homo sapiens’ “family” line. (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)