Sexual reproduction is a genetic crapshoot. Out of hundreds of eggs and millions of sperm, one joins one to produce a baby whose natural endowments could reflect the best traits of both parents—or the absolute worst. To procreate through intercourse is to take a wild roll of the DNA dice. And the stakes could hardly be higher. One stray allele could mean the difference between a healthy baby and one with a debilitating disorder.
What if science offered a way to stack the odds in favor of a healthy, gifted child? The idea is as thrilling as it is alarming. But how realistic is it? Last week, a widely shared story in the magazine Vice suggested it’s imminent and inevitable—just not in the hidebound United States.
The article, headlined “China Is Engineering Genius Babies,” reports that our superpower frenemies in the East have hatched a grand plan to breed a crop of hyperproductive smartypants. Here’s an excerpt:
“At BGI Shenzhen, scientists have collected DNA samples from 2,000 of the world’s smartest people and are sequencing their entire genomes in an attempt to identify the alleles which determine human intelligence. Apparently they’re not far from finding them, and when they do, embryo screening will allow parents to pick their brightest zygote and potentially bump up every generation's intelligence by five to 15 IQ points. Within a couple of generations, competing with the Chinese on an intellectual level will be like challenging Lena Dunham to a getting-naked-on-TV contest.”
You might think that such a sensational report would be received skeptically by readers and dismissed or debunked by the mainstream press. Instead it went viral on Facebook and Reddit and earned top billing in BBC Future’s weekly “Best of the Web” roundup.
In fact, key parts of the story are true—and not just the parts about Lena Dunham doffing her clothes. But large swaths are naïve, misleading, or grossly overstated. And it’s worth sorting through them, because in the not-distant future, it’s conceivable that parents will face a critical choice when it comes to making babies. The choice will be between fertilizing embryos in a lab and analyzing their DNA to try to select and gestate the healthiest possible baby, or doing it the old-fashioned way and leaving the genetics to chance.
Let’s start with what’s not true. China is not “engineering” babies. Even if it were, Chinese scientists wouldn’t know how to genetically engineer a genius. And even if they did know how to genetically engineer a genius, the fact is that you can’t ensure genius, because genius depends on environment as well as genes.
What is true, though, is fascinating, exciting, and troubling. Scientists are already developing the capacity to screen human embryos for a wide variety of genetic disorders, such as cystic fibrosis and sickle-cell anemia. At Reprogenetics, a private laboratory in New Jersey, couples who carry a genetic disease can have their embryos checked for the mutation before implanting them in the woman’s uterus. The process is referred to as preimplantation genetic diagnosis, and the technology is advancing rapidly. Santiago Munné, the lab’s director, told me that within a year he expects to be able to offer embryo analyses that screen for more than 100 diseases at once, for a few thousand dollars.
Women are already using preimplantation analysis to select the gender of their embryos. And in the United States, they’re overwhelmingly choosing to have daughters.
The next leap will be to whole-genome sequencing of embryos. That opens the door to screening not just for sex or single-gene disorders but for more complex disorders like autism—or even, conceivably, qualities like physical attractiveness or intelligence. Munné considers this type of “positive selection” beyond the pale: “Selecting for embryos based on eye color, etc., means you are discarding the others based on traits, and that’s unethical.”
But not everyone shares his qualms. The premise of the Vice story is that the Chinese government is eager to identify the alleles, or genetic variations, that most closely correlate with high IQ scores, so that the country’s parents can select from a number of their own embryos on the basis of intelligence. That isn’t loading the genetic dice, exactly, because the parents can’t change their own genes. And it isn’t engineering, per se, because it doesn’t involve manipulating the genes of the offspring. (That may also be possible someday, but most experts believe it’s further off.) It’s more like rolling the dice 10 times and then getting to choose from among the resulting combinations.
That’s still a powerful prospect. As NYU evolutionary psychologist Geoffrey Miller—a participant in the Chinese genome-sequencing study—tells Vice, “Even if it only boosts the average kid by five IQ points, that’s a huge difference in terms of economic productivity, the competitiveness of the country, how many patents they get, how their businesses are run, and how innovative their economy is.”
Where Vice goes astray is in the article's blithe insinuation that this is all right around the corner. It’s true that BGI Shenzhen has embarked on a research project to find relationships between genes and IQ. But experts say the implication that a handful of specific genetic variations “determine human intelligence” is spurious, let alone the claim that “apparently they’re not far from finding them.” Intelligence, you see, isn’t just a matter of a few alleles here and there.
Hank Greely, director of Stanford’s Center for Law and the Biosciences, says preimplantation genetic screening could one day render procreation via sex obsolete, at least for those who can afford it. But that doesn’t mean it will result in a generation of geniuses. “I think it’s pretty clear that intelligence—if it even exists as an entity, which remains controversial among psychologists—involves a boatload of genes and genetic combinations, all of them substantially mediated through the environment. The chances that genetic selection is going to lead to really substantial increases in human intelligence in your lifetime are low.”
Munné agrees. “IQ is controlled by probably more than 1,000 genes, so there is no point even trying to control for that,” he says.
The problem is simple math, adds Lee Silver, a genetics expert and molecular biologist at Princeton. Even if you could pinpoint a handful of genes that were likely to result in a higher IQ, the chances of any given embryo containing the right combination are minuscule. “Add in the fact that nongenetic factors account for 40 to 50 percent of the variance of something like intelligence,” and the project is basically hopeless. The bottom line, he says: Preimplantation genetic testing is “unlikely to be useful as a method of positive selection. But it will have an expanding role in avoiding disease likelihood in children.”
In any case, there’s no evidence that BGI Shenzhen or the Chinese government is actually planning to try to use the study’s findings to implement some kind of genetic-selection program. Miller, the sole source cited in the Vice story, tells me he was basing that assumption on “my speculation based on the history of Chinese population policy” combined with “off-the-record discussions with a couple of people involved.” At this point, it’s just an academic study.
While Miller agrees that aspects of the Vice story may have been framed a little sensationally, he defends the idea that embryo selection could eventually lead to significant gains in intelligence. “The key point is that the [BGI Shenzhen] project is not just looking for a handful of genes to genetically manipulate,” he says. “They’re looking for the millions of genetic variations that contribute to intelligence and how they add up in aggregate. That’s what gives you the potential power to do the embryo selection.”
Even those who disagree with Miller about intelligence think it makes sense to start grappling with the ethical implications of preimplantation genetic screening today. Silver, for one, counts himself as an advocate of the procedure, at least in certain cases. “In my opinion, even a partially informed choice is always better than chance,” he says. “Those who reject this point of view often don't think of the natural process as chance, but rather as God or Mother Nature doing her work. But as I said to Stephen Colbert on his show, ‘Mother Nature is a nasty bitch.’ ”
Yet the line between screening for disorders and selecting for traits can be blurry. If it’s OK to screen for Down syndrome, is it OK to screen for a genetic predisposition to alcoholism, depression, or obesity? Where do you draw the line between developmental disabilities and low IQ? Maybe it’s a good thing that the ability to build genius babies is a long way off. That should give us some time to decide what’s worse—a risky dice roll or a rigged game.
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