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Gene Editing Humans: It’s Not Just about Safety

The temptation to use these technologies to “enhance” ourselves or our children, or to edit out undesirable traits, will be enormous

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Chinese scientist He Jiankui surprised the scientific community and the world when he announced in November 2018 that he had genetically modified two embryos and then allowed them to develop into babies. Not only that, he believed he had acted in accordance with guidelines offered by a 2017 report by the National Academies of Sciences, Engineering, and Medicine.

More recently Denis Rebrikov, a Russian scientist, announced his intention to edit a human embryo and implant it in a woman, allowing it to develop. These renegade scientists have prompted what STAT News called a “do-over” by the National Academy of Sciences, the National Academy of Medicine and the U.K.’s Royal Society.

Last week these organizations convened the first of a series of important meetings of their jointly sponsored International Commission on the Clinical Use of Human Germline Genome Editing. In addition, the World Health Organization has formed an Expert Advisory Committee on Developing Global Standards for Governance and Oversight of Human Genome Editing.


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These groups are aiming to be much clearer this time around and to establish a governance framework so that scientists such as He and Rebrikov will understand and respect the guidelines that their peers have established: human germ-line modification is not yet safe. Because there are still many unresolved issues, including so-called off-target results, partial edits and other problems, basic bench gene-editing research can go on, so long as embryos are not allowed to develop.

Even as these bodies regroup to produce clearer guidance, however, I sense a shift in the debate. For a very long time, the scientific and bioethical consensus was that we must not do human germ-line modifications—that we should not change gametes and embryos in ways that would be permanent, affecting all future generations. In contrast, somatic modifications, which affect only the person in whom the edits are made, have been mainly uncontroversial.

But that border between germ-line and somatic genome modification is blurring; the zeitgeist feels different. There is a growing sense of inevitability that we will eventually do human germ-line modification and that our only obligation is to wait until it is safe. When that day comes, we may want to make permanent heritable changes to the human species to eradicate otherwise intractable diseases. We should, however, enter this discussion with eyes wide open, considering each application on its own merits and anticipating a wide range of issues that go well beyond safety. Many of these issues are explored in Human Flourishing in an Age of Gene Editing, which will be published by Oxford University Presson August 28, 2019.

Although we do not yet know the genetic predictors of many conditions, as we learn more, the temptation to use gene-editing technologies to “enhance” ourselves will be extraordinary—and particularly problematic if we gain the ability to reduce the likelihood of highly stigmatized traits, such as homosexuality, or to edit in highly desirable ones, such as tallness or athleticism. Many parents will, perhaps legitimately, assert that they are not prejudiced against homosexuality, or some other way of being, but just think that it makes life harder. So why not edit out the genes that increase the odds of it occurring? And don’t all good parents strive to give their children advantages?

Many of the choices coming our way will be ones that should rightly reside with prospective parents. But even when decisions are personal and private, they should be well informed, which is why we need far more ways to engage the public in conversations about germ-line genome editing. Vigorous community discussion of the values at stake is necessary for truly informed personal decision-making.

We need broad community conversation on issues beyond safety for another reason, too. What people choose to do on their own can change the collective, even when those changes were not intended for the population as a whole. Human germ-line genome editing is the quintessential example of a technology that will have both personal and collective impacts, affecting our shared environment.

How, for example, might the ability to select the features we want in our children affect the relationship between parents and children and the virtues we want to see in our communities? Commentators such as Michael Sandel of Harvard University have warned that control over the genomes of our children could lead to a sense of “hyperagency,” whereby we would lose the sense of children as gifts to be nurtured as they come to us and rather see them as objects we have designed. Will children who have been edited to have greater musical talent or athletic prowess feel obliged to fulfill their parents’ dreams even more than children usually do?

Moreover we could craft our progeny on the basis of popular but suspect norms such as homophobia or certain physical features. We could also inadvertently set up what some commentators have called a “genetic arms race,” in which parental attempts to give children an advantage just leave everyone competing at ever higher levels of whatever trait is being sought.

Surely such control is a long way off, but we are now charting a path toward human enhancement that might ultimately reduce variation in the species or, over a long period of time, lead to subspeciation. Indeed, transhumanists advocate exactly that result—a melding of new biological and synthetic powers that will essentially change the very nature of our species.

We need forums and strategies for discussing beyond-safety implications: books for scholars, policy makers and interested members of the public that will anticipate the wide array of social, economic and ethical implications of enhancement: educational experiences for students and their teachers; literature and films that do not sensationalize but help us consider the social and ethical complexity of our newfound powers; deliberative polling and other forms of democratic deliberation; and multiple channels of communication between experts and nonexperts.

Both the international commission and the WHO’s committee promise to review a wide range of social and ethical issues, well beyond safety. I hope they stick to that intention. Their meeting last week got off to a great start, with calls for more scientific transparency and renewed commitments to generating a global framework to establish parameters for this research.

But it will take sustained courage to address all of the implications of this technology. In a pluralistic society, it can be frightening to open the Pandora’s box of discussion about deeply held values. With so many different views that are seemingly impossible to reconcile, it will be easier to focus only on safety, which is the bare minimum that just about everyone can agree on. But we avoid the larger, harder conversation at our grandchildren’s peril.