Genetic Crossroads

The intersection of biotechnology, reproduction and society

Would You Genetically Modify Your Baby?

Consequential debate is hijacked by slick rhetoric

A debate on the question “Should We Prohibit Genetically Engineered Babies?,” sponsored by Intelligence Squared, took place in New York City on February 13 and is now being broadcast on NPR stations across the country. Unfortunately for those seeking a thoughtful approach to one of the most consequential societal challenges we face, the speakers taking the “no” side seemed more interested in scoring debating points than in honestly grappling with the question at hand.

Arguing for the motion – that is, in favor of public policies that would prevent genetically engineered babies – were Sheldon Krimsky, Professor of Urban & Environmental Policy at Tufts University and Chair of the Council for Responsible Genetics; and Robert Winston, Professor of Science and Society and Emeritus Professor of Fertility Studies at Imperial College. Arguing against were Nita Farahany, Professor of Law and Genome Sciences and Policy at Duke University and a member of the Presidential Commission for the Study of Bioethical Issues; and Lee Silver, professor of molecular biology and public policy at Princeton University.

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Silver has been well known as an ardent supporter of inheritable genetic modification since the 1997 publication of Remaking Eden: How Genetic Engineering and Cloning will Transform the American Family. In that book and other venues, he makes clear his enthusiasm for using genetic and reproductive technologies to “enhance” future generations, and doesn’t sugarcoat its likely consequences. Here is a taste of his vision:

“The GenRich—who account for 10 percent of the American population—all carry synthetic genes. Genes that were created in the laboratory….The GenRich are a modern-day hereditary class of genetic aristocrats….All aspects of the economy, the media, the entertainment industry, and the knowledge industry are controlled by members of the GenRich class… Naturals work as low-paid service providers or as laborers.”

Unfortunately, such scenarios – which have been promulgated not just by Silver, but also by several other high-profile scientists and pundits – were not examined during the debate. In fact, the social and ethical meanings of genetically engineered babies were only lightly engaged. Instead, the discussion focused on Farahany’s central argument: She emphasized, over and over, that prohibiting inheritable genetic modification would preclude a little-known technique called “mitochondria replacement.” Farahany staked the debate on the point that if any potential benefit at all to inheritable genetic modification can be identified, then opposing prohibitions is imperative.

This debating tactic hijacked the rest of the discussion, ambushing Krimsky’s and Winston’s efforts to raise the broad social and ethical ramifications of altering the genes that we pass down to children and future generations. The relentless focus on the “beautiful babies” that could be born after mitochondria replacement served to eclipse the longstanding and widespread understanding that efforts to create “genetically engineered babies” would be profoundly dangerous. None of the debaters, for example, pointed out that the overwhelming majority of scientists and policy makers consider inheritable genetic modification to be a bright line that should not be crossed. Nor did it come up that this view has been codified by law in more than forty countries.

But what about mitochondria replacement? Is it a justifiable form of inheritable genetic engineering?

Several variations on this procedure are currently being investigated by researchers in the US and the UK. The idea is to construct an egg or embryo using DNA from two women, in order to allow a woman with a certain subset of mitochondrial disease to have a child who has almost all of her genes, but another woman’s unaffected mitochondrial DNA.

Mitochondria replacement would not create “designer babies” in the common meaning of the term. The transferred DNA would be limited to the small amount that exists outside the nucleus of the cell, which has no effect on most traits. But the genetic change would be passed on to all future generations. And permitting this one kind of inheritable genetic modification could be used as a wedge that opens the door to more and different kinds.

Though Farahany made shrewd use of mitochondria replacement as a debate strategy, she misrepresented many aspects of its development and utility. She referred to the procedure as “safe” although there are very serious concerns about its safety, not the least because a majority of the embryos researchers have created with the technique show abnormalities. She described it as a way to “altogether eliminate” passing on mitochondrial disease, when in fact most women with mitochondrial disease wouldn’t even be candidates for the procedure, since the majority of cases are caused not by unhealthy inherited mitochondria but by mutations in nuclear DNA or by spontaneous or environmentally caused mutations in mitochondrial DNA.

In addition, Farahany incorrectly claimed that mitochondria replacement in humans is being done in the UK. It is true that researchers at Newcastle University are eager to begin clinical trials, but they have not done so because the UK is one of the many countries in which inheritable genetic modification is not permitted. The Human Fertilisation and Embryology Authority is currently considering the safety, ethical, and social implications of allowing mitochondria replacement as an exception to this prohibition.

Farahany also said that mitochondria replacement is being used in the United States; she referred to a woman she knows with a four-year-old child born after such a procedure. If this is true, whoever performed the procedure did so in dubious legal and ethical circumstances: In 2002, the FDA shut down an experiment in which several dozen babies were born after an older kind of mitochondria replacement technique, citing serious health risks and social concerns. The US researchers currently working on mitochondria replacement acknowledge that they would need to do further testing before asking for approval to begin clinical trials.

Farahany attempted to bolster her position by tapping into well-rehearsed political narratives. She argued that genetically modifying one’s child should be understood as an extension of “choice,” and characterized policies prohibiting inheritable genetic modification as unwarranted government intrusion into reproduction. But as many have noted, inheritable genetic modification doesn’t fit into the “choice” framework: Deciding whether to terminate a pregnancy is very different from deciding what kinds of traits a child should or shouldn’t have. She also appealed to opponents of abortion rights with the (dubious) claim that mitochondria replacement wouldn’t require that embryos be destroyed, as does an alternative approach, pre-implantation genetic diagnosis.

In the event that mitochondria replacement is approved, its immediate impact would be small: It simply isn’t a procedure for which there is much demand. It can’t treat or cure anyone who has mitochondrial disease, and a minority of women who are affected by the condition have a form caused solely by problematic mitochondrial DNA. Among those who do, who are concerned with passing on very serious conditions, many would likely choose less risky options – adoption, using third-party eggs, or using preimplantation genetic diagnosis to screen out severely affected embryos.

But regulatory approval for mitochondria replacement would be the first instance of official recognition for inheritable genetic modification. And if debate tactics like those used by Farahany and Silver are a portent, it would make honest discussion of what’s at stake in decisions about inheritable genetic modification far more difficult.

This debate will reach large numbers of people, many of whom have never before heard of mitochondria replacement, or thought at any length about what genetically engineered babies would mean. That their introduction to this critical challenge is marked by slick rhetoric rather than honest consideration is a shame, and a perilous one.

Jessica Cussins is a researcher at the Center for Genetics and Society.

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