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)

Research with human–animal chimera raises a number of ethical concerns, especially when neural stem cells are transplanted into the brains of non-human primates . Besides animal welfare concerns and ethical issues associated with the use of embryonic stem cells, the research is also regarded as controversial from the standpoint of NHPs developing cognitive or behavioural capabilities that are regarded as “unique” to humans. However, scientists are urging to test new therapeutic approaches for neurological diseases in primate models as (...) they better mimic human physiology than all current animal models. As a response, various countries have issued reports on the topic. Our paper summarizes the ethical issues raised by research with human–animal brain chimeras and compares the relevant regulatory instruments and different recommendations issued in national reports from three important European research nations: Germany, Switzerland and the United Kingdom. We assess and discuss the focus and priorities set by the different reports, review various reasons for and perspectives on the importance of the brain in chimera research, and identify critical points in the reports that warrant further specification and debate. (shrink)

Human‐animal chimeras—creatures composed of a mix of animal and human cells—have come to play an important role in biomedical research, and they raise ethical questions. This article focuses on one particularly difficult set of questions—those related to the moral status of human‐animal chimeras with brains that are partly or wholly composed of human cells. Given the uncertain effects of human‐animal chimera research on chimeric animals’ cognition, it would be prudent to ensure we do not overlook or underestimate their moral (...) status. However, to assess moral status, we first need to determine what kinds of capacities are morally relevant. The standard view holds that it matters, morally, if chimeric animals develop uniquely human cognitive capacities. I argue that this view is mistaken, highlighting three problems with it: that we can think of examples of uniquely human cognitive capacities that are not morally significant, that we can think of examples of morally significant cognitive capacities that are not uniquely human, and that evidence that some cognitive capacity is shared with nonhuman animals does not undermine claims that this capacity is morally significant. We need a better framework for thinking about the moral status of part‐human beings. (shrink)

In “Human‐Animal Chimeras: The Moral Insignificance of Uniquely Human Capacities,” Julian Koplin explores a promising way of thinking about moral status. Without attempting to develop a model in any detail, Koplin picks up Joshua Shepherd's interesting proposal that we think about moral status in terms of the value of different kinds of conscious experience. For example, a being with the most basic sort of consciousness and sentience would have interests that matter morally, while a being whose consciousness featured the riches (...) of loving affection, say, might have greater moral status and therefore deserve some sort of priority if the interests of the two beings conflicted. This approach represents an improvement over the more common, transparently anthropocentric habits of thinking about moral status, whether in connection with evaluating human‐animal chimera research, deciding what one can ethically eat, or pursuing some other moral inquiry. (shrink)

The prospect of creating and using human–animal chimeras and hybrids that are significantly human-like in their composition, phenotype, cognition, or behavior meets with divergent moral judgments: on the one side, it is claimed that such beings might be candidates for human-analogous rights to protection and care; on the other side, it is supposed that their existence might disturb fundamental natural and social orders. This paper tries to show that both positions are paradoxically intertwined: they rely on two kinds of (...) species arguments, “individual species arguments” and “group species arguments,” which formulate opposing demands but are conceptually interdependent. As a consequence, the existence of HACHs may challenge exactly those normative standards on which the protection of HACHs may eventually be based. This ethical paradox could constitute the ultimate source of the “moral confusion” that some authors have suspected HACHs to provoke. (shrink)

The article aims to present issues arising out of differences in the way that the terms chimera and hybrid are defined in legal systems and by natural sciences in the context of mixing human and animal DNA. The author analyses the different approaches to defining these terms used in various legal systems, dividing them into groups in light of conclusions reached from examining definitions used in natural sciences. The distinction is used to answer the question of which approach to (...) definitions applied by legislators is the best way to handle the subject of human-animal organisms, given the need to balance their impact on medicine and the ethical concerns that arise. (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)

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)

Why do laws and regulations marking boundaries between humans and other animals proliferate amid widespread proclamations of the waning of the species concept and the consensus that life is a continuum? Here I consider a recent spate of new guidelines and regulations in the United Kingdom and United States that work to estrange human bodies from other animals in biomedicine. Using the idea of a bioconstitutional moment to understand how state institutions deliberate over “human–animal chimeras,” I address how nations (...) differently establish separations between humans and other animals. New chimeric entities, containing human hereditary material, have consecrated regulatory ground and signify increased attention to fields of research that have long used interspecies mixing. Regulators and policy makers now find themselves in a curious position. On the one hand, they continue to regulate the estrangement between humans and other animals, but on the other, they support the creation of chimeric life––a form of life that draws into question the very basis of such separations. (shrink)

The moral status of human-animal chimeras that have human brain cells is especially concerning. The concern is that such animals have the same high moral status as human beings. Why? Julian Koplin suggests that support for this concern is based on this claim: capacities unique to humans gives one a high or full moral status. Koplin then proceeds to convincingly object this claim. However, I argue that the concern is instead based on a different claim: for those humans who do (...) have a high moral status, it is their (or some of their) mental capacities that confer this high moral status. Since having a human brain that is not too impaired is sufficient for having these mental capacities, and human-animal chimeras -- with brains composed of a sufficient number, type, and structure of human cells -- will have a human brain that is not too impaired, it follows that such animals would have the same moral status as human beings. (shrink)

Ongoing research on making “human-animal chimeras” or “animals containing human material” to solve the shortage of organs available for transplantation has raised many ethical issues regarding the creation and utilization of such constructs, including cultural views regarding the status of those creations. A pilot study was conducted to explore Japanese public attitudes toward human-animal chimeras or ACHM. The February 2012 study consisted of focus group interviews with citizens from the Greater Tokyo Area, aged between 20 and 54. The 24 participants (...) were divided into four groups. Transcripts of the interviews were analyzed and participants’ attitudes categorized. Five categories of participant attitudes were identified: resistance to the unnatural, concerns about animal welfare, concerns about controlling human-animal chimeras, concerns about the possible birth of intermediate entities, and resistance to creating and utilizing animals containing my material or my child’s material. Our FGI results showed a broader and greater variety of public concerns than those reported in previous studies. While researchers have tried to establish new methods to avoid creating intermediate entities, our participants expressed concerns about not only intermediate entities but also animals containing their own material or their child’s material. Based upon their responses in the interviews, we are introducing a new ethical concern: “animals containing my material/my child’s material.”. (shrink)

New discoveries are improving the odds of human cells surviving in host animals, prompting regulatory and funding agencies to issue calls for additional layers of ethical oversight for certain types of human–animal chimeras. Of interest are research proposals involving chimeric animals with humanized brains. But what is motivating the demand for additional oversight? I locate two, not obviously compatible, motivations, each of which provides the justificatory basis for paying special attention to different sets of human–animal chimeras. Surprisingly, the (...) sets of animals that actually get flagged for special scrutiny by research and funding guidelines do not correlate with either of the sets of animals that arise when we think about what is motivating additional oversight. What this shows is that existing research policies and funding guidelines are disconnected from their motivation: the rationale for flagging certain types of human–animal chimeras as requiring special oversight is ignored in execution. (shrink)

The International Society for Stem Cell Research (ISSCR) has recently released the 2021 update of its guidelines. The update includes detailed new recommendations on human–animal chimera research. This paper argues that the ISSCR recommendations fail to address the core ethical concerns raised by neurological chimeras—namely, concerns about moral status. In minimising moral status concerns, the ISSCR both breaks rank with other major reports on human–animal chimera research and rely on controversial claims about the grounds of moral (...) status that many people will rightly reject. A more robust framework for regulating human–animal chimera research still needs to be developed. (shrink)

This article compares and contrasts the patenting of animals, humans, and biotechnological inventions in the United States, at the European Patent Office, and within the European Union. It shows that morality is not a concern of U.S. legislative instruments or courts and patents have been granted liberally on living organisms, from microorganisms to mammals, in North America since the 1980s. By way of contrast, both European legislative instruments enshrine a morality bar that must be employed to deny patentability. Their implementation, (...) however, is unpredictable due to a lack of detailed guidance on what morality means. The remit of the morality bar extends principally to humans, but the interests of animals must now also be factored into the equation. The manner in which this is done is unclear and patents on plants, although controversial among the public in general, do not unduly trouble lawmakers now that a significant time has elapsed since this Rubicon was crossed. This article explains and critically assesses these systems while identifying some of the ethical problems that are likely to emerge in due course focusing on the ad hoc regard paid to animals and the lack of a structured approach to considering their rights or welfare. (shrink)

I respond to Monika Piotrowska's argument against anthropocentric theories of moral status that they yield disparate moral verdicts about parallel cases of embryonic stem cell transplantation. I argue that anthropocentric theories of moral status may not fall prey to this problem because embryonic stem cell transplantation may constitute creation rather than mere enhancement.

It may soon be possible to generate human organs inside of human-pig chimeras via a process called interspecies blastocyst complementation. This paper discusses what arguably the central ethical concern is raised by this potential source of transplantable organs: that farming human-pig chimeras for their organs risks perpetrating a serious moral wrong because the moral status of human-pig chimeras is uncertain, and potentially significant. Those who raise this concern usually take it to be unique to the creation of chimeric animals with (...) ‘humanised’ brains. In this paper, we show how that the same style of argument can be used to critique current uses of non-chimeric pigs in agriculture. This reveals an important tension between two common moral views: that farming human-pig chimeras for their organs is ethically concerning, and that farming non-chimeric pigs for food or research is ethically benign. At least one of these views stands in need of revision. (shrink)

In response to Koplin and Wilkinson, I argue, first, that the uncertain clinical prospects of human-pig chimera based transplantation makes the reason to spend resources for clarifying whether such practice might imply serious ethical breach due to enhanced cognitive capacities of the chimeras rather weak. T he benefits of further pursuing this avenue of research is so uncertain, so that taking even very unclear risks of serious ethical breach is not worth the price in terms of spent resources, and (...) therefore only limited resources should be spent to clarify such risk before the project is abandoned due to unacceptable risks. Second, I argue that as there are some reason to pursue this avenue further, the analogy to the notion of halting all farming of larger animals for food does not hold up. The reason is that we do not need to probe any further any comparable risk to know that such farming practices should be halted. A fundamental underlying issue to the question discussed by Koplin and Wilkinson1 in this paper is formulated when they write: > We should therefore be confident that human-pig chimeras would lack morally relevant cognitive capacities before setting out to use them as a source of transplantable human organs. This leaves open the question of how confident …. (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)

Our recent article begins by describing a new technique for creating human–animal chimeras. This technique—known as interspecies blastocyst complementation—may enable us to generate human organs inside of human–pig chimeras. One central concern about farming human–pig chimeras for their organs is that their moral status would be uncertain and potentially significant. Our article is partly, but not only, about such concerns. At the heart of our paper are two broader questions. First, how should we treat beings of uncertain moral status? (...) And second, do our reasons for thinking that human–pig chimeras have uncertain moral status also provide reason to think regular, non-chimeric pigs have uncertain moral status? We thank Mike King, Christian Munthe, David Resnik, Per Sandin and Rob Streiffer for their commentaries on our paper, each of which serves to clarify the ethical issues at play. In this response, we want to respond to one criticism, acknowledge the force of several others, and point towards some philosophical work that remains to be done. First, the criticism. Resnik questions the parallel we draw between human–pig chimeras and regular pigs. In the case of regular pigs, there is currently a social consensus that it is morally acceptable to farm pigs for food. For Resnik, this consensus imposes a special burden on those who wish to argue against it; ‘one needs substantial evidence that the majority view is wrong’.1 Since an equivalent consensus does not exist in relation to human–pig chimeras, one might think that moral uncertainty concerns have less force in the context of meat production than human–animal chimera research. We do not think the social consensus in favour …. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy and Literature 25.2 (2001) 278-294 [Access article in PDF] Homer's Human Animal: Ritual Combat in the Iliad Jonathan Gottschall I Freud called Darwin's revelation of man's animality a blow to human narcissism on par with Copernicus's finding that Earth is not the center of the solar system. While Darwin hinted at our bestiality in the Origin of Species, in later publications he conveyed the disturbing and fantastic news (...) that our ancestors were, as he playfully wrote in private notebooks, "monkey men." 1 Adam and Eve were not lovingly molded from the clay; they were the rude grandchildren of a "hairy, tailed quadruped, probably arboreal in its habits, and an inhabitant of the Old World." 2 Darwin's news was greeted by his contemporaries with a range of responses, from hooting derision to holy indignation, to resigned acceptance. Yet his hypothesis has been amply verified by the work of geneticists, primatologists, biologists, archaeologists, paleoanthropologists, and others. Nowadays we are not too chagrined to hear that we share a common ancestor with the other apes; it is orthodox evolutionary theory.But perhaps we give Darwin rather too much credit for this discovery. Surely he deserves esteem for deciphering the mechanism of evolution in natural selection, for helping demonstrate our kinship with other primates, and for providing subsequent scientists a head start for their research. He also deserves the less technical distinctions of giving human self-regard a terrific bloody nose and of helping to sire the modern existential crisis. But while Darwin may be responsible for giving scientific credibility to the notion that humans do not stand aloof from the rest of the animal kingdom, he was far from the first to come to this realization. [End Page 278]The artists of every age and the builders of mythology have come, with wondrous unity of conception, to similar conclusions. In fact, the world's earliest known pictorial art conveys this message. The hundreds of paintings and etchings adorning the walls of the Chauvet Cave in France, though over thirty thousand years old, include depictions of human-animal compounds, including a figure that is half-human and half-bison. 3 This ancient suggestion that the human and animal realms overlap is likewise indicated in the common mythological figure of the human-animal hybrid. As Dorothy Dinnerstein says: "Myth images of half-human beasts like the mermaid and the Minotaur express an old, fundamental, very slowly clarifying communal insight: that our species' nature is internally inconsistent; that our continuities with, and our differences from, the earth's other animals are mysterious and profound." 4 So Darwin did not invent the concept of the human animal. Rather, he marshaled the evidence and developed the theoretical model that established scientific credence for an ancient belief.The Ancient Greeks were particularly fascinated by hybrids blending human and animal morphology. Their mythology abounds with queer, conflicted, compound creatures. And so does their literature. Their first and greatest poet, Homer, was characteristically Greek in his attention to half-human creatures. The sirens, the centaurs, the minotaur, the chimera, Scylla, "Ox-eyed" Hera, and "Owl-eyed" Athena are all present or alluded to in his work. All of these figures symbolically insinuate that beasts dwell under every human skin.But Homer's suggestions of human animality do not cease with these compound creatures. In the Iliad, he presses this theme with depictions of warriors who are, physically, fully human. Homer suggests, however, that their dispositions and behavior patterns are, often, fully brutish. For Homer, the human animal is the most incongruous crossbreed of all: he is queer, conflicted, inconsistent, godlike, and brute. It is the "in-betweenness" of the human animal that makes him tragic. His soul would gravitate toward the empyrean, but his body roots him steadfastly in the blood and filth of animal life. The father Zeus, perhaps recognizing this, says: "In truth there is nothing more wretched on earth than man, of all things that breathe and move." 5The Iliad suggests human animality in a variety of ways. First, we are aligned with... (shrink)

The modern biological definition of a chimera is a single organism composed of cells with multiple distinct genotypes. Chimeras combining human and nonhuman cells are invaluable for various kinds of research, providing a platform for the study of human cell development while avoiding the ethical issues involved in conducting this research on human subjects. There is also the possibility that human/nonhuman chimeras could one day be used to produce human organs for transplant. Yet human/nonhuman chimeras raise a number of (...) unique ethical challenges as well. Critics worry that they are ‘unnatural’, or will cause a kind of ‘moral confusion’, or pose a threat to human dignity. There are also concerns about the kinds of treatment we might owe to human/nonhuman chimeras. For example, introducing human pluripotent stem cells into a gorilla blastocyst could result in the animal developing a ‘humanlike’ brain, or developing human behaviours or characteristics. Would we need to treat such a being as we do our fellow humans? This chapter examines various arguments concerning research involving human/nonhuman chimeras, and the implications of these arguments for research policy. I conclude that research involving human/nonhuman chimeras is not intrinsically morally wrong, though it may be morally impermissible in some cases. However, I criticize the standard approach to evaluating the treatment of nonhumans in research, arguing that the moral treatment of nonhuman animals, including human/nonhuman chimeras, depends on contextual factors, rather than their moral status. (shrink)

Human eggs for basic, fertility and stem-cell research are in short supply. Many experiments that require their use cannot be carried out at present, and, therefore, the benefits that could emerge from these are either delayed or never materialise. This state of affairs is problematic for scientists and patients worldwide, and it is a matter that needs our attention. Recent advances in chimera research have opened the possibility of creating human/non-human animal chimeras intended for human gamete production (chimeras-IHGP). In (...) this paper, I examine four arguments against the creation of such chimeras and prove that all of them are found wanting. I conclude by showing that there is a strong moral reason for scientists to pursue this research avenue. (shrink)

One argument Robert and Baylis do not raise in their article on the creation of interspecies chimeras using human cellular material is that the creation of these chimeras would, or could, offend human dignity. Yet, human dignity is one of the most common concerns raised in public debates, academic arguments, and policy documents regarding biotechnology in general, and the creation animal-human chimeras in particular. … The concept is ill-defined within bioethics and … risks being dismissed as meaningless or uselessly vague. (...) However, this lack of definition should not yet cause us to abandon or ignore human dignity. At least in arguments about creating chimeras, an examination of what may be meant by appeals to human dignity can uncover important concerns or arguments that are not captured by other formulations of the debate. (shrink)

Non-human animal chimeras, containing human neurological cells, have been created in the laboratory. Despite a great deal of debate, the status of such beings has not been resolved. Under normal definitions, such a being could either be unconventionally human or abnormally animal. Practical investigations in animal sentience, artificial intelligence, and now chimera research, suggest that such beings may be assumed to have no legal rights, so philosophy could provide a different answer. In this vein, therefore, we can ask: What (...) would a chimera, if it could think, think about? Thinking is used to capture the phenomena of a novel, chimeric being perceiving its terrible predicament as no more than a laboratory experiment. The creation of a thinking chimera therefore forces us to reconsider our assumptions about what makes human beings (potentially) unique (and other sentient animals different), because, as such, a chimera’s existence bridges our social and legal expectations about definitions of human and animal. Society has often evolved new social norms based on different kinds of (ir)rational contrivances; the imperative of non-contradiction, which is defended here, therefore requires a specific philosophical response to the rights of a thinking chimeric being. (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)

In “Human‐Animal Chimeras: The Moral Insignificance of Uniquely Human Capacities,” Julian Koplin argues against the views that all uniquely human traits have moral significance or that all the traits humans have in common with other animals “are morally insignificant.” He recommends instead the adoption of “a better framework for thinking about the moral status of part‐human beings,” one that emphasizes the “phenomenal value (or disvalue)” chimeric animals are likely “to enjoy (or suffer).” If the moral status of these chimeric animals (...) is grounded in the phenomenal value of their interests—that is, their interests as nonhuman animals—current protections for animals used in research may be inadequate to protect those interests. (shrink)

Cerebral organoid models in-of-themselves are considered as an alternative to research animal models. But their developmental and biological limitations currently inhibit the probability that organoids can fully replace animal models. Furthermore, these organoid limitations have, somewhat ironically, brought researchers back to the animal model via xenotransplantation, thus creating hybrids and chimeras. In addition to attempting to study and overcome cerebral organoid limitations, transplanting cerebral organoids into animal models brings an opportunity to observe behavioral changes in the animal itself. Traditional animal (...) ethics frameworks, such as the well-known three Rs (reduce, refine, and replace), have previously addressed chimeras and xenotransplantation of tissue. But these frameworks have yet to completely assess the neural-chimeric possibilities. And while the three Rs framework was a historical landmark in animal ethics, there are identifiable gaps in the framework that require attention. The authors propose to utilize an expanded three Rs framework initially developed by David DeGrazia and Tom L. Beauchamp, known as the Six Principles (6Ps). This framework aims to expand upon the three Rs, fill in the gaps, and be a practical means for assessing animal ethical issues like that of neural-chimeras and cerebral organoid xenotransplantation. The scope of this 6Ps application will focus on two separate but recent studies, which were published in 2019 and 2020. First, they consider a study wherein cerebral organoids were grown from donors with Down syndrome and from neurotypical donors. After these organoids were grown and studied, they were then surgically implanted into mouse models to observe the physiological effects and any behavioral change in the chimera. Second, they consider a separate study wherein neurotypical human embryonic stem cell-derived cerebral organoids were grown and transplanted into mouse and macaque models. The aim was to observe if such a transplantation method would contribute to therapies for brain injury or stroke. The authors place both studies under the lens of the 6Ps framework, assess the relevant contexts of each case, and provide relevant normative conclusions. In this way, they demonstrate how the 6Ps could be applied in future cases of neural-chimeras and cerebral organoid xenotransplantation. (shrink)

Alongside in vitro studies, researchers are increasingly exploring the transplantation of human brain organoids (HBOs) into non-human animals to study brain development, disease, and repair. This paper focuses on ethical issues raised by such transplantation studies. In particular, it investigates the possibility that they might yield enhanced brain function in recipient animals (especially non-human primates), thereby fundamentally altering their moral status. I assess the critique, raised by major voices in the bioethics and science communities, according to which such concerns are (...) premature and misleading. I identify the assumptions underlying this skeptical critique, and mention some objections against them, followed by some possible replies. I proceed to argue that the skeptical position is ultimately implausible, because it presupposes an unreasonably high standard of full moral status. My argument appeals to David DeGrazia’s idea of a “borderline person”, and to the need for consistency with existing animal research regulations. I outline the practical implications of my view for the conduct of studies that might result in the development of full moral status in a transplanted animal. I also discuss some of the ethical implications of animal enhancement (particularly of rodents) below the threshold associated with full moral status. I conclude that far from being premature, further debate on these issues is urgently needed to help clarify the prospects that a neural chimera might attain full moral status in the foreseeable future, and the level of quality of life required to make it acceptable to knowingly create such a being via HBO transplantation. (shrink)

Many people find the notion of blending humans and nonhumans together to create animals whose brains are composed entirely of human brain cells disturbing. I argue that these moral qualms lack adequate justification. I consider a number of reasons for objecting to the creation of such chimeras and argue that none of these reasons withstand scrutiny. I argue that the only plausible objections to these chimeras would require that they possess morally significant properties that would be lacked by similar, non-chimeric (...) animals, but that there is no good reason to think this would be the case. (shrink)

This chapter considers the prospect of generating human organs within chimeric animals comprised of a mix of human and animal cells. Although seemingly farfetched – the term ‘chimera’ even means, in some modern usage, a “mere wild fancy” or “unfounded conception” (Oxford English Dictionary (n.d.) ‘chimera | chimaera, n.’, OED Online. Oxford University Press. Available at: https://www.oed.com/view/Entry/31708) – recent research into interspecies blastocyst complementation is paving the way toward growing human organs inside of human-animal chimeras, potentially within the (...) not-too-distant future Zheng et al. (Development 148(12), 2021). These human-animal chimeras promise important advances within regenerative medicine and medical research. They also raise some profound bioethical issues, which we survey below. (shrink)

The writer responds to the article “Human‐Animal Chimeras: The Moral Insignificance of Uniquely Human Capacities,” by Julian J. Koplin, in the September‐October 2019 issue of the Hastings Center Report.

: 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)

Switzerland has very detailed laws regulating the use of animals in agriculture, entertainment and science. There are also many Swiss laws governing the genetic modification of animals, protecting human embryos, and criminalising the creation of human/animal chimeras or hybrids. Despite all these regulations, the creation of an animal embryo that will develop a human organ using induced pluripotent stem cells and the subsequent birth of the resulting chimera would actually be permitted by current legislation. While this might appear to (...) be an unhappy accident due to insufficient scientific foresight, I argue here that this loophole should not be closed, as the creation of human organs inside animals will probably be possible within 10 years, and Swiss laws would currently enable the use of this process to save human lives through this allogenic or autologous organ source. (shrink)

The figure of the chimera animates both mythology and the biotechnological imagination. The mythological construction of animals from the sections or attributes of different species parallels the surgical and genetic manipulations of animals in modern transformations. Chimerization also represents a hybridization that relationally links different species. Both the mythological imagination and biotechnical practice bear heavily on the definition and identity of the human animal. In mythology the chimera links the animal, the human, and the divine. In biotechnology like (...) xenotransplantation and genetic engineering, real patchwork combinations of humans and other animals are constructed. (shrink)

Recent advances in the technology of creating chimeras have evoked controversy in policy debates. At centre of controversy is the fear that a substantial contribution of human cells or genes in crucial areas of the animal’s body may at some point render the animal more humanlike than any other animals we know today. Authors who have commented on or contributed to policy debates specify that chimeras which would be too humanlike would have an altered moral status and threaten our notion (...) of ‘human dignity’. This setting offers a productive opportunity to test the notion of human dignity and to emphasize some of its weaknesses as an ethical tool. Limiting chimerism experiments on the basis of whether or not it undermines or challenges human dignity implies a clear demarcation of those characteristics which are typically, and importantly, human. Evidence of our evolutionary ties and behavioral similarities with other animals seem to annul all attempts to define the uniquely human properties to which human dignity may be attributed. Hence, it has been suggested that the particular moral status associated with humans cannot be explained for beyond an intuitive basis. In what follows, we will argue that the difficulties inherent in the notion of human dignity lie not in the impossibility to acquire a list of properties which are unique to humans, but rather in the difficulty to demonstrate the moral relevance of these properties, and particularly the relevance of their being human. We offer an alternative interpretation of the concept of dignity which is not necessarily related to being human. (shrink)

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)