Smarter, taller, healthier: what those new IVF embryo tests can actually deliver

Smarter, taller, healthier: what those new IVF embryo tests can actually deliver

Key takeaways

• A new type of genetic test claims to predict which IVF embryo will be tallest, smartest or healthiest – but the science does not support these claims
• The potential benefits are minimal at best, while the risks of acting on this information are real
• These tests are not available through Australian clinics, but Australian patients can still access them overseas – and some are
• In my view, accepting the proven risks of IVF without a fertility reason, just to access this testing, is not a trade-off that makes sense
• If you are offered or considering any embryo genetic testing, I encourage you to ask your specialist exactly what the evidence supports

If you are going through IVF, or thinking about it, you may have come across a new type of genetic test being marketed to prospective parents. The pitch is compelling: test your embryos and find out which one is most likely to become the tallest, smartest or healthiest child.

One company in the United States is running posters across New York with the tagline “Have your best baby.” It offers to screen embryos for up to 2,000 traits – IQ, height, eye colour, baldness, and the risk of diseases like Alzheimer’s and heart disease, decades before they could ever develop.

I want to help you understand what is actually going on here, because I think patients deserve a clear picture before making decisions this significant.

What is this test and how is it different from standard embryo testing?

If you have looked into IVF, you may already know that embryos can be tested for inherited genetic conditions – things like cystic fibrosis, where a single faulty gene causes disease. That type of testing is well established and is used to avoid passing on serious conditions. It is something I discuss with patients where it is clinically warranted.

This newer testing is completely different. Rather than looking for a known genetic fault, it tries to predict complex traits that are shaped by thousands of genes all working together. It generates what are called polygenic risk scores – essentially a number that is supposed to represent your embryo’s future risk of developing a condition, or its likelihood of having a certain trait, like a higher IQ or above-average height.

The idea is that you compare scores across your embryos and choose which one to transfer based on those predictions.

These tests are not currently available through Australian clinics, but nothing stops Australian patients from sending samples or genetic data to overseas companies for analysis. Some are doing exactly that.

What does the evidence actually show?

My research group looked at this technology carefully, using the same framework we apply when evaluating any medical test.

The short answer: the predictions are far less reliable than the marketing suggests, and the potential benefits are very small.

Mathematical modelling suggests the gains might amount to a few IQ points or 1-3 centimetres in height at best. For conditions like Alzheimer’s that develop late in life, we cannot even properly assess the benefits – the outcomes won’t be known for decades.

And even those modest estimates are on shaky ground, for a few important reasons.

Genes are only part of the story

Polygenic risk scores are built from data collected on people currently in their 50s and 60s. These are people who grew up without smartphones, without today’s levels of processed food, air pollution or microplastics. Their education, healthcare and lifestyle looked fundamentally different.

This matters because traits like intelligence or disease risk do not come from genes alone. They emerge from a lifelong interaction between your genes and your environment. The same genetic variants that contributed to diabetes in one generation may behave very differently in the next.

So when a test gives your embryo a score for IQ, it is looking at only one side of a very complex equation – and ignoring the environmental half, which may be just as important, or more so.

Think of it this way: predicting how tall a plant will grow based on its seed alone, without knowing anything about the soil, water or sunlight it will receive. The seed matters, but it is far from the whole story.

Factors like early childhood nutrition, parental engagement, education access and socioeconomic circumstances have an enormous and proven influence on how children develop. No embryo genetic score can account for any of that.

Selecting for one trait can affect another

There is also something called pleiotropy, where a single gene influences multiple traits at once. Research suggests that selecting embryos for higher educational attainment, for example, may inadvertently increase the likelihood of choosing an embryo with a higher predisposition to bipolar disorder.

These are not trade-offs that are visible to parents receiving a score sheet. They are hidden in the biology.

How does this sit with Australian guidelines?

In Australia, the National Health and Medical Research Council (NHMRC) supports preimplantation genetic testing to avoid serious inherited conditions. Using these tests to predict complex traits like intelligence or height is inconsistent with those guidelines and sits in a regulatory grey zone.

Why I think this matters for your decision-making

Here is the part I want to be direct about.

IVF carries real, established medical risks. These include an increased risk of high blood pressure in pregnancy and preterm delivery. The process of taking a biopsy from an embryo to analyse its DNA may also affect pregnancy outcomes.

If you are doing IVF because you need fertility assistance, those risks are part of a considered decision you are making with good reason. But if you are considering IVF purely to access polygenic risk score testing when you do not have a fertility issue, you would be accepting those proven risks in exchange for benefits that are, at best, marginal and uncertain.

That is not a trade-off I can recommend.

I also hold a Masters of Bioethics alongside my clinical qualifications, and I think about these questions carefully. This technology raises real concerns – selecting embryos based on traits like intelligence or height echoes eugenics movements with devastating historical consequences. It also risks creating impossible decisions for parents: how do you choose between an embryo with a slightly higher risk of breast cancer but a higher predicted IQ, and one with different scores across a dozen other traits? These are not medical decisions. They are impossible value judgements that can leave parents paralysed, second-guessing themselves, or in some cases choosing not to transfer any embryo at all.

What should you do if you are offered this testing?

If you are going through IVF and someone raises polygenic embryo screening, my advice is to ask directly: what does the evidence support here, and what are the actual benefits for my situation?

The answer, based on what the research currently shows, is that the benefits are minimal and uncertain, and the marketing significantly overstates what these tests can deliver.

The best outcomes for children do not come from embryo selection scores. They come from loving, stable families with access to good nutrition, education and healthcare – factors that have far more influence on how a child develops than the tiny genetic variations these tests are measuring.

If you would like to understand what embryo genetic testing is genuinely warranted for your situation, I am happy to talk through it. Get in touch to book a consultation.

References

Polyakov A. Published via The Conversation, February 2026. Want a tall, smart child? How IVF tests are selling a dream