The Myth of the Designer Baby—Why ‘Genetic Optimization' Is More Hype Than Science

Scientific American

28-07-2025

An understandable ethics outcry greeted the June announcement of a software platform that offers aspiring parents 'genetic optimization' of their embryos. Touted by Nucleus Genomics' CEO Kian Sadeghi, the $5,999 service, dubbed ' Nucleus Embryo,' promised optimization of traits like heart disease and cancer resistance, as well as intelligence, longevity, body mass index, baldness, eye color, hair color and left-handedness. It also promised to weed out what makes someone an alcoholic.
That left one commentator, a venture capitalist, feeling ' nauseous.' Critics worried that it ' treats children as marketable goods.' More than one reference to ' designer babies ' and ' eugenics ' naturally followed. ' The GATTACA Future Is Here,' read one headline, referencing the classic sci-fi film from 1997 that imagined a dystopian future where genetically engineered 'Valids' reign supreme over the 'In-Valids' who were conceived the old-fashioned way.
As professional bioethicists, we would have those same concerns—if Nucleus Embryo actually did what it claims. But it doesn't. The cinematic analogy to Nucleus Embryo isn't GATTACA. It's The Dropout —the 2022 miniseries about the rise and fall of Elizabeth Holmes and Theranos.
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To be clear, there's no sign of the intentional deception that marked Theranos, but there are striking parallels in commercializing a research tool into something it isn't. Like Holmes, Sadeghi dropped out of a prestigious university to start his own biotech company, wooing enough Silicon Valley investors to launch his start-up. (Is it mandatory that all CEOs of biotech start-ups be college dropouts?) Like Holmes, Sadeghi draws on personal experience with the medical industry and its disappointing results as part of the inspirational narrative he uses to motivate his call for a health revolution. And like Holmes' Theranos, Sadeghi's Nucleus Embryo starts from existing technology, and uses that reliable foundation to then leap into the realm of fantastic claims that may entice venture capitalists and wealthy but naive customers but don't hold up to scrutiny when you start seriously poking around.
Sadeghi sees it differently: 'Not that long ago, IVF once sparked fear and the stigma of test tube babies,' he said in a launch video aimed at would-be parents. 'Today's it's how one in 50 people in the U.S. are conceived. What was once controversial is now an everyday practice. The same is true with genetic optimization. The technology is now here, and it's here to stay.'
But it's not. At least not the way Sadeghi depicts it: Parents-to-be have utilized preimplantation genetic diagnosis as part of in vitro fertilization for decades. After a set of fertilized embryos are created by IVF, a sample of DNA from each is extracted and tested. The parents can then select which embryo or embryos to implant based on their genetic profiles. The technology has been extraordinary for families plagued by hereditary diseases, such as Huntington's disease and Tay-Sachs disease—deadly conditions with known genetic causes. The technology can also show major chromosomal abnormalities that might make an embryo less likely to be viable if implanted. In more recent years, diagnostic services have expanded to test for other, rarer genetic conditions, which may not appear so frequently in families but are still debilitating. IVF and preimplantation genetic diagnosis are very expensive, and there are legitimate ethical concerns about who is able to access the technology and who is not. But there is little ethical handwringing about parents who use the technology to prevent transmitting a horrific disease to their child, or who opt not to implant an embryo that might not develop.
But let's say a couple undergoing IVF doesn't just want a child without a deadly disease. Let's say they want a child who will be at low risk of cancer and heart disease, and also highly intelligent, slender, acne-free and destined for a long life. Enter Sadeghi's Nucleus Embryo. The genetic optimization software offers the parents an opportunity to test for all these traits and hundreds more in up to 20 embryos.
This is where we enter Theranos territory. Unlike Huntington's disease and Tay-Sachs disease, there are no major genetic markers for many cancers or a truly definitive set for heart disease, let alone for intelligence, acne, body-mass index or longevity. Geneticists have known this for decades. Granted, there are hundreds of locations across the human genome where genetic variants have ever-so-slight positive or negative associations with those traits, and information about what's at each of those locations can be combined into one big measurement called a ' polygenic risk score,' which many geneticists use for research purposes. But the clinical value of polygenic risk scores for even straightforward medical conditions like asthma and stroke remains highly dubious. Most of the research so far has been done almost exclusively on people with Western European ancestry, so there's little guarantee that the predictions extrapolate to people with family trees that trace to different parts of the globe. And even for people of European ancestry, the predictive power of polygenic risk scores remains so severely limited that you won't find them part of standard clinical care anywhere in the world. The Washington Post noted "serious reservations' in medicine over such use earlier this month, and no peer-reviewed research supports it.
Nucleus Genomics says it offers customers the ability to engage in genetic optimization because the potential parents can select among embryos based on the genetic information that Nucleus Embryo provides. But that isn't genetic optimization; no embryos or genetic material is optimized in some technologically innovative new way. It's just old-school preimplantation genetic diagnosis of fertilized embryos, irresponsibly expanded to offer prospective parents the illusion of control over things like IQ and mental health when the science isn't there to support the claims. The company also makes counseling about this mountain of confusing information optional, which is not optimal.
Sadeghi's Nucleus Embryo is what happens when you Silicon-Valley-ify diagnostic genetics. Scientific reliability is swapped out in exchange for braggadocio about disrupting a medical status quo that may not even need it. Peer-reviewed research is less important than a punchy promotional video. Widespread uncertainty about the clinical value of polygenic risk scores gets buried under a snazzy app that lets you name each embryo you're testing. Established clinical guidelines about what traits warrant genetic testing and what don't are cast aside as affronts to your reproductive and capitalistic liberty: 'Some people don't think you should have this choice,' Sadeghi says. 'But it's not their choice to make. It's yours.'
When confronted with the Theranos comparison in this essay, Nucleus Genomics and Sadeghi called it unfair, defending Nucleus Embryo as helping people, not harming them. We disagree but not for the reasons raised by the critics who have assumed that Nucleus Embryo works the way its marketing says it does.
If Nucleus Embryo really let you optimize your potential child's intelligence or dial up her longevity, dial down her acne and steer clear of the dreaded left-handedness, then there would be some deep ethical questions to ask about designer babies, the legacy of eugenics and the marketization of children. But you can rest easy. This isn't GATTACA. There's no danger of the genetically optimized, unblemished, lithe and right-handed Valids ruling over the In-Valids, whose parents couldn't afford Nucleus Embryo.
The real danger is that a bunch of wealthy parents-to-be who are too eager to control their children's biological future will shell out $5,999 for a product that offers no such control. Those parents might avoid perfectly healthy embryos, scared of implanting ones that don't appear to be sufficiently optimized. Or it could result in children being born to those parents and expected to live up to their purchased optimized future, but instead winding up very much like the variety of humans who proceeded them.