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)

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)

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.

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.

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)

Greely’s target article outlines six categories of ethical issues associated with human brain surrogate research. Some of these issues are familiar from other research contexts; others, less...

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)

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 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)

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 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)

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)

Given the broad coverage of “Human Brain Surrogates Research: The Onrushing Ethical Dilemma,” this commentary focuses on the section “human/nonhuman brain chimeras,” and specifically, the questions...

Developments in biological technology in the last few decades highlight the surprising and ever-expanding practical benefits of stem cells. With this progress, the possibility of combining human and nonhuman organisms is a reality, with ethical boundaries that are not readily obvious. These inter-species hybrids are of a larger class of biological entities called “chimeras.” As the concept of a human-nonhuman creature is conjured in our minds, either incredulous wonder or grotesque horror is likely to follow. This paper seeks to mitigate (...) those worries and demotivate reasonable concerns raised against chimera research, all the while pressing current ethical positions toward their plausible conclusions. -/- In service of this overall aim, first, I intend to show that chimeras are far less foreign and fantastic in light of recent research in the lab; second, I intend to show that anti-realist (so-called “constructivist”) commitments regarding species ontology render the species distinction (i.e., the divide between human and nonhuman) superfluous as a basis for ethical practice; and third, I discuss some prevailing dignity accounts regarding the practical ethics of the creation, research, and treatment of chimeras. Consequently I intend to show that the adoption of this particular set of views (constructivist ontology, capacity-based ethics) in conjunction with recent research ought to justify a parallel with what we accord to humans persons, and that trajectory allows for cases of moral permissibility. (shrink)