Human cerebral organoids (HCOs) are three-dimensional in vitro cell cultures that mimic the developmental process and organization of the developing human brain. In just a few years this technique has produced brain models that are already being used to study diseases of the nervous system and to test treatments and drugs. Currently, HCOs consist of tens of millions of cells and have a size of a few millimeters. The greatest limitation to further development is due to their lack of vascularization. (...) However, recent research has shown that human cerebral organoids can manifest the same electrical activity and connections between brain neurons and EEG patterns as those recorded in preterm babies. All this suggests that, in the future, HCOs may manifest an ability to experience basic sensations such as pain, therefore manifesting sentience, or even rudimentary forms of consciousness. This calls for consideration of whether cerebral organoids should be given a moral status and what limitations should be introduced to regulate research. In this article I focus particularly on the study of the emergence and mechanisms of human consciousness, i.e. one of the most complex scientific problems there are, by means of experiments on HCOs. This type of experiment raises relevant ethical issues and, as I will argue, should probably not be considered morally acceptable. (shrink)

A central question in contemporary ethics and political philosophy concerns which entities have moral status. In this article, I provide a detailed analysis of the view that moral status comes in degrees. I argue that degrees of moral status can be specified along two dimensions: (i) the weight of the reason to protect an entity’s morally significant rights and interests; and/or (ii) the rights and interests that are considered morally significant. And I explore some of the complexities that arise when (...) we link degrees of moral status to the weight of reasons to protect bundles and/or the content and size of these bundles, in particular regarding the attribution of moral status to nonparadigmatic entities (e.g. people with severe cognitive disabilities, children, embryos and foetuses, robots, non-human animals, ecosystems, and rivers). (shrink)

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)

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)

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)

Robust technological enhancement of core cognitive capacities is now a realistic possibility. From the perspective of neutralism, the view that justifications for public policy should be neutral between reasonable conceptions of the good, only members of a subset of the ethical concerns serve as legitimate justifications for public policy regarding robust technological enhancement. This paper provides a framework for the legitimate use of ethical concerns in justifying public policy decisions regarding these enhancement technologies by evaluating the ethical concerns that arise (...) in the context of testing such technologies on nonhuman animals. Traditional issues in bioethics, as well as novel concerns such as the possibility of moral status enhancement, are evaluated from the perspective of neutralism. (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)

Much bioethical discussion has been devoted to the subject of human enhancement through various technological means such as genetic modification. Although many of the same technologies could be, indeed in many cases already have been, applied to non-human animals, there has been very little consideration of the concept of “animal enhancement”, at least not in those specific terms. This paper addresses the notion of animal enhancement and the ethical issues surrounding it. A definition of animal enhancement is proposed that provides (...) a framework within which to consider these issues; and it is argued that if human enhancement can be considered to be a moral obligation, so too can animal enhancement. (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)

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)

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)

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)

In this work I present a detailed critique of the dignity-related arguments that have been advanced against the creation of human–nonhuman chimeras that could possess human-like mental capacities. My main claim is that the arguments so far advanced are incapable of grounding a principled objection against the creation of such creatures. I conclude that these arguments have one, or more, of the following problems: they confuse the ethical assessment of the creation of chimeras with the ethical assessment of how such (...) creatures would be treated in specific contexts, they misrepresent how a being could be treated solely as means towards others’ ends, they fall short of demonstrating how humanity’s dignity would be violated by the creation of such entities, and they fail to properly characterise the moral responsibilities that moral agents have towards other moral agents and sentient beings. (shrink)

This article is the lead piece in a special report that presents the results of a bioethical investigation into chimeric research, which involves the insertion of human cells into nonhuman animals and nonhuman animal embryos, including into their brains. Rapid scientific developments in this field may advance knowledge and could lead to new therapies for humans. They also reveal the conceptual, ethical, and procedural limitations of existing ethics guidance for human‐nonhuman chimeric research. Led by bioethics researchers working closely with an (...) interdisciplinary work group, the investigation focused on generating conceptual clarity and identifying improvements to governance approaches, with the goal of helping scholars, funders, scientists, institutional leaders, and oversight bodies (embryonic stem cell research oversight [ESCRO] committees and institutional animal care and use committees [IACUCs]) deliver principled and trustworthy oversight of this area of science. The article, which focuses on human‐nonhuman animal chimeric research that is stem cell based, identifies key ethical issues in and offers ten recommendations regarding the ethics and oversight of this research. Turning from bioethics’ previous focus on human‐centered questions about the ethics of “humanization” and this research's potential impact on concepts like human dignity, this article emphasizes the importance of nonhuman animal welfare concerns in chimeric research and argues for less‐siloed governance and oversight and more‐comprehensive public communication. (shrink)

The prospect of using cell-based interventions to treat neurological conditions raises several important ethical and policy questions. In this target article, we focus on issues related to the unique constellation of traits that characterize CBIs targeted at the central nervous system. In particular, there is at least a theoretical prospect that these cells will alter the recipients' cognition, mood, and behavior—brain functions that are central to our concept of the self. The potential for such changes, although perhaps remote, is cause (...) for concern and careful ethical analysis. Both to enable better informed consent in the future and as an end in itself, we argue that early human trials of CBIs for neurological conditions must monitor subjects for changes in cognition, mood, and behavior; further, we recommend concrete steps for that monitoring. Such steps will help better characterize the potential risks and benefits of CBIs as they are tested and potentially used for treatment. (shrink)

Animals, in the age of biotechnology, are the subjects of a myriad of scientific procedures, interventions, and modifications. They are created, altered, and experimented upon—often with highly beneficial outcomes for humans in terms of knowledge gained and applied, yet not without concern also for the effects upon the experimental subjects themselves: consideration of the use of animals in research remains an intensely debated topic. Concerns for animal welfare in scientific research have, however, been primarily directed at harm to and suffering (...) of animal subjects and their prevention. Little attention has been paid to the benefits research might potentially produce for animals themselves and the interests that some animals may therefore have in the furtherance of particular avenues of science. (shrink)

Koplin and Wilkinson (K&W) argue for the sociological claim that many believe (1) that the moral uncertainty argument provides significant moral reasons against farming human–pig chimaeras for their organs (henceforth, ‘farming for organs’) but (2) that there no are significant moral reasons against farming non-chimeric pigs for food (henceforth, ‘farming for food’). And yet, K&W argue for the ethical claim, that if the moral uncertainty argument provides significant moral reasons against farming for organs then there are similar moral reasons against (...) farming for food. The moral uncertainty argument appears to be an application of what I have called ‘the moral status framework’ to farming for organs.1–3 According to the moral status framework, human–animal chimaera research should be evaluated as to its risk of (1) enhancing the moral status of an animal to that of a normal human while (2) continuing to treat the animal as animals are usually treated in biomedical research.4 In status-enhancing research, ‘sacrificing the fundamental interests of the chimeric research subject as they would have been sacrificed in any other animal research is the moral equivalent of sacrificing the fundamental interests of a fully functional adult human being. On all but the most extreme animal rights views, this makes status-enhancing research much worse than other biomedical research on animals, and on any plausible view, makes it absolutely unacceptable’.5 K&W similarly say that, according to the moral uncertainty argument, ‘It would be gravely wrong to treat humans the same way we do animal …. (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-nonhuman chimeric research—research on nonhuman animals who contain human cells—is being used to understand human disease and development and to create potential human treatments such as transplantable organs. A proposed advantage of chimeric models is that they can approximate human biology and therefore allow scientists to learn about and improve human health without risking harms to humans. Among the emerging ethical issues being explored is the question of at what point chimeras are “human enough” to have human rights and thus (...) be owed higher standards of research protection than that currently afforded to nonhuman animals. However, this question and other related questions assume that the ethics of experimenting on nonhuman animals have been settled, which they have not. In this essay, we argue that it is imperative to give adequate attention to familiar questions about nonhuman animal research as well as new questions about chimera research and that failure to do so will result in a distorted understanding of the ethics of chimera research. (shrink)

When Mrs. Frederick C. Little's second son was born, everybody noticed that he was not much bigger than a mouse. (E. B. White, 1945, 1.) In every somatic and morphological detail Stuart Little was...

In this conversation, four experts in animal research oversight—Christopher Stodgell, Lori Hill, Robert Kesterson, and Angelika Rehrig—discuss the complexities of stem cell-based chimeric animal experiments, especially in relation to traditional animal welfare practices. Each expert shares their experiences and suggestions for how best to conduct chimeric animal research, including discussing the importance of communication and collaboration between experts in animal behavior and welfare and the investigators conducting or proposing chimeric research studies.

In order to reach its full potential, human embryonic stem cell (hESC) research requires the use of human oocytes. There is currently a shortage of human eggs for research, and this shortage is likely to continue, as many states and countries prohibit their sale for research purposes, while at the same time condoning unregulated markets for oocytes for use in assisted reproduction. In this essay I first explore possible alternative sources of oocytes for hESC research and conclude that, at present, (...) women are the best source. I then examine arguments about exploitation and commodification that are often raised to prohibit payment to women for oocytes in both the reproductive and research contexts and find these arguments wanting. I conclude by suggesting that ethical concerns raised about a market in oocytes do not warrant a prohibition on the sale of eggs, but that a regulated market can consistently minimize ethical concerns while respecting women and providing important resources for advances in hESC research. (shrink)

This study adopted an empirical method to investigate lay people’s attitudes toward the bioethical issues of human-animal chimeric brains. The results of online surveys showed that (1) people did not entirely reject chimeric brain research, but showed slightly more negative responses than ordinary animal testing; and that (2) their ethical concerns arose in connection with the perception that chimerism in the brain would humanize the animal. This means that people’s psychology was consistent with the ethical argument that crossing the human-animal (...) boundary would bring moral confusion to our society. Meanwhile, it was not in line with another argument that moral status depended on having high capacities, and that chimerism would cause a problem if it enhanced animals’ capacities. Furthermore, this study analyzed additional psychological factors related to people’s moral judgment and the relationship among those factors. Several psychological factors, such as the perception that chimeric brain research is unnatural, were identified as mediating the relationship between perception of animal humanization and ethical concerns about creating and using chimeric brains. Introducing an empirical approach to the ethics of human-animal chimeric brains brought two findings: (1) this study informed us of socially shared intuition regarding this novel technology; and (2) it unveiled the psychological processes behind people’s ethical concerns in more detail than they spontaneously mentioned. These findings will help to build normative arguments and future policies that are understandable and acceptable to society. (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)

Scientists will soon be able to grow human-transplantable organs in pigs. This paper focuses on the question of whether it is morally permissible to eat genetically altered pigs after harvesting their organs. Despite a lack of scholarly discussion of this question, the impetus for it is straightforward. There is no reason to think that peoples’ taste for pig will subside when scientists reach the point of being able to growing mature human organs inside them. In this paper, I argue that (...) there is a good reason why we should eat genetically altered pigs and currently no compelling reasons to the contrary. (shrink)

To date, ethics discussions about stem cell research overwhelmingly have centered on the morality and acceptability of using human embryonic stem cells. Governments in many jurisdictions have now answered these “first-level questions” and many have now begun to address ethical issues related to the donation of cells, gametes, or embryos for research. In this commentary, we move beyond these ethical concerns to discuss new themes that scientists on the forefront of NRM development anticipate, providing a preliminary framework for further discussion (...) between scientists and ethicists. Fostering strong partnerships between neuroscientists and ethicists that operate and collaborate within this evolving framework will maximize the translation of NRM discoveries on the brain into cures that are safe and address the needs of science and society. (shrink)

This essay proposes that Socrates practiced various spiritual exercises, including meditation, and that this Socratic practice of meditation was habitual, aimed at cultivating emotional self-control and existential preparedness. Contemporary research in neurobiology supports the view that intentional mental actions, including meditation, have a profound impact on brain activity, neuroplasticity, and help engender emotional self-control. This impact on brain activity is confirmed via technological developments, a prime example of how technology benefits humanity. Socrates attains the balanced emotional self-control that Alcibiades describes (...) in the Symposium because of the sustained mental effort he exerts that directly impacts his brain and his emotional and philosophical life. The essay concludes that Socratic meditative practices aimed at manifesting true dignity as human beings within the complexities of a technological world offer a promising model of self-care worthy of embracing today. (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 discussion by Greely et al. (2007) of the Stanford advisory committee's deliberations regarding whether to pursue research involving the transfer of human brain stem cells to fetal mice not onl...

The use of nonhuman animals in research has long been a source of bioethical and scientific debate. We consider the oversight and use of nonhuman animals in chimeric research. We conducted interviews with twelve members of embryonic stem cell research oversight committees, nine members of institutional animal care and use committees, and fourteen scientists involved in human–nonhuman‐animal chimeric research in different areas of the United States. Interviews addressed animal welfare and conceptual issues associated with moral status and humanization of nonhuman (...) animals that contain human cells. Our findings suggest that concepts of enhanced moral status and consciousness are not very useful in human–nonhuman‐animal chimeric research in part because their meanings are not easily defined, which presents challenges to applying the concepts in research. Instead, scientists and oversight committee members we interviewed seemed to rely on standard assessments of changes in animal welfare when focusing on the ethics of human‐animal chimeric research. (shrink)

David DeGrazia (2009) and Stuart Rachels (2011), among others, offer moral arguments in favor of adopting a vegetarian diet that have, they claim, broad appeal. Rather than relying on an account of animal rights or a particular ethical theory, these arguments rely on the moral principle that an extensive amount of pain requires moral justification. Since people do not need to eat meat in order to survive, the arguments conclude that the pain that animals experience in factory farming is unjustified. (...) I argue that these very same arguments support a more radical conclusion, namely, vegetarians morally should avoid eating vegetables from industrialized farming. Thus, if vegetarians are convinced by the moral arguments for vegetarianism offered by DeGrazia and Rachels, then they should be convinced, by analogous reasoning, that they should not eat vegetables from industrialized farming. (shrink)

In this conversation, three researchers from the fields of developmental biology and stem cell science—Ali Brivanlou, Lorenz Studer, and May Schwarz—speak about the importance of conducting chimeric animal experiments. The scientists describe some of the stem cell-based chimeric research being conducted in the United States, responsibilities they have in using modified animals for experiments, and things they would like the public to understand about this research. This conversation illuminates not only what chimeric animal researchers are doing in the lab but (...) also how their work may benefit society and where this science might go in the future. (shrink)

I am grateful to the authors who commented on my article (Piotrowska 2014) for their careful examination of my argument. They have presented a variety of stimulating ideas and suggestions, with which I largely agree and which I would like to discuss further, but in the interest of brevity, I shall try to concentrate only on points of contention.

Researchers have increasingly been creating chimeras – combinations of cells from two species – raising profound ethical, social and scientific controversies. Such research could lead to the creation of animals such as pigs that contain human organs for transplantation, yet public fears have emerged. Scientists have thus called for enhanced public education and discussion, but these efforts require comprehension of the nature of public concerns. While arguments have viewed chimeras as either “good” or “bad,” artists have long depicted chimeras in (...) ways that can inform these discussions. Chimeras have a long history – the term itself is from Greek mythology – and have generated complex and ambivalent responses, reflecting deep questions regarding who we are as humans. Images across disparate cultures suggest how humans have long seen species boundaries as fluid but in differing ways. These images suggest that emotional, not just rational, utilitarian perspectives need to be addressed and that challenges may arise in altering views of all individuals. Nonetheless, public messages could draw on historic examples of positive such combinations. Thus, artistic representations can aid scientists, policymakers, educators and members of the public-at-large recognize and better comprehend and address the discomforts chimeras can foster. (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 (and/or other kinds of chimeric animals). 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 (or near 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 (or require greater support) in the context of meat production than human–animal chimera research. We do not think the social consensus in favour …. (shrink)

Bioethicists often defend novel practices by drawing analogies with practices that we are already familiar with and currently tolerate. If some novel practice is less bad than some widely-accepted practice, then (it is argued) we cannot rightly reject it. Using the bioethics literature on xenotransplantation and interspecies blastocyst complementation as a case study, I show how this style of argument can go awry. The key problem is that our moral intuitions about familiar practices can be distorted by their seeming normality. (...) When considering the ethics of emerging technologies and novel practices, we should remain open to the possibility that our moral views about familiar practices are mistaken. (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.

Many controversies in bioethics turn on questions of moral status. Some moral status issues have received extensive bioethical attention, including those raised by abortion, embryo experimentation, and animal research. Beyond these established debates lie a less familiar set of moral status issues, many of which are tied to recent scientific breakthroughs. This review article surveys some key developments that raise moral status issues, including the development of in vitro brains, part-human animals, “synthetic” embryos, and artificial womb technologies. It introduces the (...) papers in this Special Issue, contextualises their contributions to the moral status literature, and highlights some enduring challenges of determining the moral status of novel types of beings. (shrink)