Earlier this year US researchers reporting that they have successfully created human-pig chimera embryos . Ethicists are debating the moral issues surrounding this research, and, in particular, the moral status given to human-nonhuman chimeras.
In an article published in Quartz this week, Oxford ethicist Julian Savulescu noted that human-pig chimeras may be capable of feeling pain, and, indeed, could potentially engage in higher cognitive functions and social activity. We should take a precautionary approach with chimeras, Savulescu suggests.
"Any human-pig chimera should ... be assessed against the criteria of personhood... If there is a chance a new lifeform could experience pain or might not be able to interact socially, and we don't know, it should be treated as if it does experience pain and will have problems of social adaptation. Likewise, if it could plausibly have higher cognitive functions, it should be treated as if it would have them."
Case Western Reserve University bioethicist Insoo Hyun is critical of the assumptions underpinning the idea of "chimera personhood". In an influential article published in Plos Biology last year, Hyun wrote:
"It it is entirely unclear what types of new psychological characteristics could count to elevate the moral status of a research animal above where it currently is, such that its scientific use would no longer be morally acceptable. In my view, the only characteristic that might qualify doing this heavy moral lifting is the appearance of human-like self-consciousness, defined as an existential awareness and concern for oneself as a temporally extended agent with higher-order beliefs about one's own mental experiences. But this unique psychological characteristic is not likely to emerge in a chimeric animal's brain".
Lori Matthews, executive director of the Kimmela Center for Animal Advocacy and a neuroscientist, argues that we should place these ethical questions within the context of ongoing animal rights "abuses". Writing in STAT , she said:
"These concerns about chimeric research add to the already potent ethical issues associated with mainstream invasive animal research. Tens of millions of animals are sickened, injured, genetically manipulated, and killed in biomedical labs every year, even as a robust body of evidence shows that some animals are more self-aware and emotionally and cognitively complex than we previously thought. That leads to the inescapable conclusion that we have already crossed a number of moral lines."