Imagine being promised the 'perfect' child—tall, smart, and healthy—all through a simple genetic test. Sounds like a dream, right? But here’s where it gets controversial: this dream is being sold to prospective parents through IVF tests that claim to predict which embryo will grow into the 'best' child. Yet, the reality is far more complex—and potentially harmful.
Prospective parents are increasingly being marketed genetic tests that promise to identify embryos with the highest potential for traits like IQ, height, and even hair color. These tests, known as polygenic risk scores, analyze thousands of genes to predict an embryo’s likelihood of developing certain conditions or traits. For instance, companies like Nucleus Genomics in the U.S. advertise their ability to screen embryos for up to 2,000 traits, from eye color to Alzheimer’s risk, using the catchy tagline, 'Have your best baby.'
And this is the part most people miss: these tests are not as reliable as they seem. Our research group examined whether this technology is ready for clinical use, applying the same rigorous standards used for any medical screening test. The results? The predictions are highly uncertain. For late-onset diseases like Alzheimer’s, the outcomes won’t be known for decades. Even for traits like IQ and height, the benefits are minuscule—perhaps a few IQ points or 1–3 centimeters in height. While 3 centimeters might sound significant, it’s unclear how meaningful these predictions truly are.
Here’s why: polygenic risk scores are based on studies of people in their 50s and 60s who grew up in vastly different environments. They didn’t have smartphones, processed foods, or the same levels of air pollution and microplastic exposure we face today. Their education, healthcare, and lifestyles were fundamentally different. Traits and diseases result from lifelong interactions between genes and the environment, so assuming past genetic patterns will predict future outcomes in a rapidly changing world is risky.
But here’s the real kicker: genetic testing ignores the environmental side of the equation, which may be equally—if not more—important. Take IQ, for example. Early childhood education, nutrition, parental involvement, and socioeconomic factors play a massive role in cognitive development. Choosing an embryo based on a slightly 'better' genetic score while overlooking these proven influences is like predicting a plant’s height from its seed alone, without considering soil, sunlight, or water.
There’s also the issue of pleiotropy, where one gene affects multiple traits. Selecting for higher educational achievement, for instance, might unintentionally increase the risk of bipolar disorder. Is this a trade-off parents are fully aware of?
In Australia, the National Health and Medical Research Council guidelines recommend genetic testing to avoid serious inherited conditions, but polygenic risk scores operate in a regulatory grey zone. They predict future risks, not diagnoses, making their use for embryo selection ethically and legally questionable. Yet, parents are sending samples overseas for analysis, despite the lack of clear guidelines.
The ethical concerns are profound. This technology echoes eugenics movements of the past, which led to forced sterilization and horrific atrocities. Selecting embryos for traits like intelligence or skin color risks perpetuating discrimination and deepening social inequalities. Are we comfortable with this slippery slope?
Another troubling aspect is decision paralysis. When parents receive polygenic risk scores for multiple embryos across dozens of traits and conditions, how do they choose? These aren’t simple medical decisions—they’re impossible value judgments. The weight of these choices can leave parents second-guessing themselves for years or even opting not to transfer any embryos.
There’s a cruel irony here: couples undergoing IVF solely for polygenic risk score testing, rather than fertility issues, may actually reduce their chances of having a healthy baby. IVF carries risks, such as higher blood pressure during pregnancy and preterm delivery, and the biopsy process itself can affect pregnancy outcomes. Are parents trading proven risks for unproven benefits?
So, what’s the takeaway? The 'best' child isn’t defined by a genetic score. It’s a child born into a loving family with access to good nutrition, education, and healthcare. These environmental factors have far more influence on a child’s development than tiny variations in DNA.
Here’s a thought-provoking question for you: Should we prioritize genetic perfection over the proven impact of love, care, and opportunity? Share your thoughts in the comments—let’s spark a conversation that matters.
