Advanced DNA testing for embryos is here — and it’s fraught.
Say you’re about to start in vitro fertilization and your clinic offers you a futuristic new option: It can analyze the DNA of the embryos you conceive and let you choose which one to implant based on their genes.
No guarantees, but you can shoot for the best odds that a future baby will be as genetically healthy as current science can ascertain, with lower risks for common diseases like diabetes and cancer. Sound good?
About two thirds of Americans would say it does, recent Harvard research suggests. Nearly one third of those surveyed even say they would consider going through IVF for the sole purpose of such genetic screening.
Respondents also expressed concerns, though. Among them: Nearly three quarters worried that the testing could amount to eugenics, the push for genetic superiority propounded by Nazis and other 20th-century racists. Even more respondents worried that it could set up false expectations for a child. And that it could exacerbate inequality.
Plentiful fodder here for a lofty theoretical discussion by academic ethicists, it seems.
Except the discussion is no longer theoretical.
“This has somewhat flown under the societal radar, but it’s happening,” says Todd Lencz, a professor of psychiatry and molecular medicine in the Zucker School of Medicine at Hofstra/Northwell and a leading researcher on the new genetic testing of embryos. “It’s not a question of if it will happen, or what the technology will be in three years. People are doing this now.”
And so ethicists are wading into an emerging debate over practices that some
critics call “liberal eugenics” and some proponents call “parental choice” or “reproductive autonomy.”
At issue is the idea that historically, the evil of eugenics “was that it was forced on people,” says Harvard Law School bioethicist Glenn Cohen, referring not only to Nazi atrocities but also to coerced sterilization in the United States and elsewhere. The defenders of genetic selection of IVF embryos, however, point out that this involves “private choice by private individuals,” as Cohen summarizes the position.
Yet Cohen and other ethicists do see potential problems, from questions about the science’s actual powers of prediction to unequal access. There are so many fraught issues, in fact, that Lencz helped organize a groundbreaking conference on the topic in Cambridge this fall.
Over two days, experts ranging from genetic counselors to physicians to ethicists discussed the dawn of “polygenic embryo screening”: the new ability to analyze an early embryo’s DNA and calculate its odds for common conditions influenced by many genes: heart disease, schizophrenia, various cancers. Or for nonmedical traits, including height and intelligence.
Overall, the conference attendees often sounded so negative — one speaker mentioned “queasiness” — that the recent Harvard study that found a high level of public approval “was surprising to everyone,” says behavioral scientist Rémy Furrer, who led that study. In the absence of regulation, at least in the United States, “we need to start educating the public so that they can make informed decisions,” he says.
Meanwhile, the technology is developing quickly. Parental selection
Last week, a San Francisco company, Orchid, announced a technical advance: It will now offer analysis of an embryo’s whole genome rather than the more limited DNA tests that parents had been offered previously. The cost will run $2,500 per embryo, which would come on top of the costs for IVF, which are typically around $15,000 per cycle.
The level of DNA data that Orchid can now read from embryo cells is “very, very close to what you’d get on blood or saliva” from an adult, says company founder Noor Siddiqui.
This means the test can not only pick up risks for common polygenic diseases, which involve multiple genes; it can also detect single-gene mutations that lead to some birth defects and some cases of developmental disorders like autism, she says.
The methods involved are described in a scientific paper that has not yet been published, Siddiqui says.
The whole-genome technique allows detection of “de novo” mutations — those that neither parent carried and thus couldn’t be caught by prepregnancy screening — says Hebrew University statistical geneticist Shai Carmi, a leading expert not affiliated with Orchid. Those new variants are difficult to pick up from a biopsy of a tiny embryo, he says, and whether the new Orchid technology is truly good enough to find them “will have to be seen once their data is independently validated.”
Broadly speaking, the new method could represent one of the biggest impacts yet from sequencing the human genome, says Harvard genetics professor George Church, an Orchid investor and adviser.
It holds the potential to help parents avert some of the serious genetic conditions that affect nearly 3 percent of children, he adds. Until now, “if you are in that 3 percent, there was nothing you could do about it,” Church says. “And here is something you can definitely do about it.”
Polygenic embryo screening has been available commercially since 2019, but it remains rare. Fertility specialists tend to be less enthusiastic about it than the general public, with many taking a wait-and-see stance. Only two companies in the United States offer it: Orchid and a New Jersey-based company, Genomic Prediction, that says it works with scores of clinics in 37 countries.
But it may not remain rare. The cost of DNA analysis has been plummeting, and the proportion of American births using IVF has been rising: It’s already over 2 percent — nearly 100,000 babies per year. Some type of genetic testing is already done in 45 percent of IVF cycles, mainly to increase the chance of a successful pregnancy.
If the screening catches on, it could be seen as a step toward “designer babies,” a concept running through cultural touchstones such as “Gattaca” and “Brave New World.”
No genes are tweaked, though; it’s more that the potential babies are ranked or prioritized or selected.
So welcome to the new process of “parental selection.” Or, to borrow a Genomic Prediction slogan, “choice over chance” children. Not a new breed; rather, perhaps, a new brand of baby-making.
Doing the math
The worries and warnings that dominated the Cambridge conference began with the basic math and science. How significant, really, is the ability to select from a very limited pool of embryos that share parents and thus genetic heritage?
And given the many uncertainties about whether gene variants linked to higher risk will actually translate into disease, should parents even be given the option of testing for them? Will they really understand the many limitations and complexities involved?
Multiple professional societies, including a number in Europe, have warned that polygenic embryo screening is not ready for prime time, and the journal Nature cautioned last year that the practice was spreading “well ahead of a full understanding of the potential benefits — or dangers” that include “the unnecessary destruction of viable embryos.”
Still, those potential benefits are promising enough for there to be a federally funded research project — at polygenicembryo.org — to assess the screening and explore what it could mean for society.
One study the project supported, led by Hebrew University’s Carmi, found that polygenic embryo screening could cut almost in half a couple’s risk of having a child with schizophrenia or Crohn’s disease.
The greater the potential benefit, though, the more that justice issues such as unequal access become sharper.
For one example, genetic databases tend to be Eurocentric, so parents with more diverse embryos are less likely to benefit from screening at this point.
For another, it’s obviously troubling if a new technology to lower genetic risk is available only to those who can afford hundreds or thousands of dollars per embryo, given the cost of the test and IVF.
Possibly thorniest of all is the prospect that some parents will use embryo DNA to select not just for medical risk but for traits they may desire, such as academic or athletic ability.
The two American companies that offer polygenic screening do not assess nonmedical traits, but parents can obtain the raw data and get that analysis done elsewhere if so inclined. (In the Harvard survey, though, respondents were much less enthusiastic about genetic screening for traits rather than diseases; only around one third approved.)
At the Cambridge conference, “the E word” — an inside-joke reference to the buzz around the issue of eugenics — inevitably entered the discussion, along with concern about “shiny fancy children for rich people.”
But so did an ethical counterpoint that some call “procreative beneficence.” It’s the controversial idea, explained ethicist Christopher Gyngell, from the University of Melbourne, that “couples should select the child expected to have the best life.”
Another speaker, Eric Juengst from the University of North Carolina School of Medicine, threw out a series of down-to-earth questions: What if parents want to use genetic screening to ensure a child will be extraordinarily good-looking? What if a military family wants an extra-aggressive and resilient child? Or an artistic family wants an embryo with a high risk for bipolar disorder because it’s linked to creativity?
Those are still only thought experiments. But Juengst suggested that now is the time to think about where those “moral boundaries” should be, because polygenic embryo screening could soon make them a reality.
‘This has somewhat flown under the societal radar, but it’s happening.’ TODD LENCZ, a professor of psychiatry and molecular medicine in the Zucker School of Medicine at Hofstra/Northwell.
Carey Goldberg is a longtime health and science reporter, including for the Globe and WBUR, and has also been Boston bureau chief of The New York Times and Bloomberg News. She is coauthor, with Peter Lee and Isaac Kohane, of “The AI Revolution in Medicine: GPT-4 and Beyond.”