Sydney Sweeney’s ‘Good Genes’ Ad Sparks Debate as Genetic Testing Start-Ups Promise Designer Babies

Sydney Sweeney’s ‘Good Genes’ Advert: The Spark That Lit a Bigger Fire

In late 2025, a jeans advertisement starring actress Sydney Sweeney set social media ablaze. The tagline, playfully referencing her ‘good genes,’ did more than sell denim—it tapped into a centuries-old conversation about genetic inheritance, beauty standards, and the ethics of eugenics. While the ad itself was a nod to pop culture’s fascination with physical traits, the online frenzy it triggered revealed society’s unease about the intersection of genetics and desirability.

But as the dust settled on that controversy, a new—and far more consequential—debate emerged. If an advert hinting at ‘good genes’ can cause an uproar, what happens when companies begin selling the promise of them?

Genetic Testing Start-Ups Move Beyond Hype to Reality

Enter Nucleus Genomics, a New York-based start-up making headlines with their latest subway ad campaign. For a steep $8,999 fee, the company offers would-be parents a chance to genetically profile up to 20 embryos during IVF treatment. Their slick app lets users review embryos for a wide array of disease genes and traits—everything from autism and ADHD to eye color, height, and even intelligence.

This isn’t science fiction. It’s a business model attracting investment from Silicon Valley heavyweights like Peter Thiel’s Founders Fund, and riding the wave of a ‘pronatalist’ movement championed by tech moguls such as Elon Musk. With a shrinking population in much of the developed world, these investors are obsessed with ‘optimising’ the next generation: smarter, healthier, longer-lived children.

And the public is responding. According to Nucleus Genomics founder Kian Sadeghi, their ad campaign has driven a 1700% spike in sales. Yet, beneath the glossy promise of ‘designer babies,’ the science—and the ethics—are anything but simple.

Designer Babies or Preventative Medicine? The Science Behind the Promise

Screening embryos for serious genetic or chromosomal abnormalities has long been standard practice in IVF clinics. In the UK, strict regulations limit such screening to fatal or life-limiting conditions, helping families avoid inherited diseases like Huntington’s or Tay-Sachs. In the US, however, the regulatory landscape is far more permissive, allowing companies like Nucleus to market genetic ‘choice’ for common diseases and personal traits.

But how reliable is this choice? Experts caution that the predictive power of genetics for most common traits and conditions is limited. Diseases like heart disease, high blood pressure, or schizophrenia involve complex interactions among hundreds—sometimes thousands—of genes. Traits like intelligence and height are even less predictable, tangled with environmental factors and lifestyle choices.

What these tests offer are ‘polygenic risk scores’: statistical probabilities based on large datasets of DNA. As Sky News reports, the American College of Medical Genetics and Genomics concluded in 2024 that polygenic screening currently offers no proven clinical benefit and cannot guarantee how a particular gene will express in a developing child.

Nucleus Genomics acknowledges these limitations. “Nobody wants DNA to be absolutely destiny. It’s not, but even if it was, you wouldn’t want that, right?” Sadeghi explains. The company claims to provide genetic counseling and emphasizes the probabilistic nature of their results. But for critics, the line between informed choice and the illusion of control remains blurry.

The Ethics of Optimisation: Are We Ready?

The conversation around Sydney Sweeney’s advert, once considered provocative, now seems quaint compared to the ethical minefield facing genetic testing start-ups. Investors and scientists alike grapple with the implications: Are we heading toward a world where picking a child’s traits is as routine as choosing a college or a career?

Behavioural geneticist Eric Turkheimer calls Nucleus and its rivals “new eugenics companies.” Others voice visceral discomfort, with one investor admitting the idea made him “nauseous.” The ethical dilemmas are profound. Who decides which traits are desirable? What happens to embryos deemed ‘less optimal’? And as AI and genomic databases grow ever more powerful, how do we regulate the technology to prevent abuses?

In the US, the lack of clear regulation means the market moves faster than public policy. In the UK and elsewhere, tight rules limit embryo screening to clear medical necessity. But the global surge in genetic data collection and AI-driven analysis suggests that the ability to ‘code’ future generations is not far off.

As Sky News notes, the predictive ability of polygenic risk scores for diseases like breast and prostate cancer may soon reach clinical relevance. For now, though, most experts agree: we are not yet at the point where science can deliver on the full promise of ‘designer babies.’

Society at a Crossroads: Between Hype, Hope, and Hard Truths

The story that began with Sydney Sweeney’s advert has evolved into a much larger cultural and scientific reckoning. On one side, there’s the optimism of tech entrepreneurs and families desperate to prevent suffering. On the other, the caution of geneticists, ethicists, and a society wary of unintended consequences.

Ultimately, the real test will come from the families who use these services—and the children who grow up in a world where their DNA was chosen in part by an app. Are we offering meaningful choice, or just the comforting illusion of control? The answer may shape not only the future of medicine but the very definition of what it means to be human.

Assessment: The rapid evolution from pop-culture debates about ‘good genes’ to real-world genetic optimisation reflects a seismic shift in both technology and public consciousness. While start-ups like Nucleus Genomics push the boundaries of what’s possible, the science is still catching up—and the ethical questions are only growing more complex. For now, the promise of designer babies remains more marketing than reality, but the conversation is far from over.