Physics is famous for its mind-blowing ideas. Subatomic particles can be in many places at once. The passage of time depends on how fast you move. But because such ideas are confined to the realm of the invisible and the inhumanly vast, most people consider them little more than funny curiosities.
Biology has amazing ideas too. Since they can affect the everyday world of living bodies, their impact is often felt much more viscerally. An example are the “chimeras”, organisms that, a bit like the mythological beast, are formed from cells of two different species. Scientists have already produced goat-sheep and rat-mouse. Now, a group of American, Chinese and Spanish researchers have reported significant progress in the quest to create chimeras using human cells, in this case combining them with monkey cells to form functional embryos.
It’s another example of humanity’s growing power to play with the basics of life, a power that makes many people uncomfortable. The work leaves the very idea of a species that looks at least a little fuzzy around the edges. The experiments involving human cells can break taboos deeply rooted in human dignity, human exceptionalism and, among religious people, raising concerns about interfering with God’s creation.
There are also more practical concerns. Human monkey embryos were not meant to grow to maturity. But it is correct to ask what would have happened if they had done it and what should be done if or when someone decides to try it. What is the moral and legal status of an organism with a human and a non-human genome? What effect, if any, might human cells have on the animal’s brain? Aware of such concerns, many countries, including the United States and the United Kingdom, strictly regulate what is allowed. Much of the latest work was done in China.
Despite those concerns, the potential benefits outweigh the risks. Such an investigation should always be conducted with caution and properly supervised. But it must also be encouraged, because the rewards it brings can be significant. Chimeric embryos may offer a solution to the ethical problems that make human embryo experiments difficult. That could lead to new treatments for congenital diseases. This particular research was inspired by the desire to grow human organs in the bodies of animals, from where they could eventually be used for transplants. Alleviating the prolonged global shortage of transplantable organs could save many lives. In the United States alone, more than 100,000 people are on waiting lists for transplants.
The best way to ensure that such research can move forward is to talk about it with the public, not just with expert scientists and regulators. Ethical debates around chimeras go on for years, but mostly in scientific journals and academic conferences, places outsiders rarely venture. If dramatic displays of this kind of scientific advance take people by surprise, they are likely to generate a backlash. Scientists must also work to ensure that international rules are harmonized, to the extent possible.
The story offers cause for optimism. Many biological technologies that were initially criticized as reckless intrusion into the natural order of things ended up being far less terrifying in practice than they once seemed in theory. In vitro fertilization was once considered unnatural; It’s routine these days, at least in the rich world. Genetically modified crops sparked street protests and dire warnings about “Frankenfoods.” Billions of meals later, the technology has proven to be safe and effective. Ultimately, however, scientists must convince not only each other, but the public as well.
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