What New York Magazine Gets Right About Embryo Screening, and What It Misses

Christopher Cox's New York Magazine piece raises the right worry about embryo screening: that some companies focus more on marketing than on improving their science.  Moreover, as he argues, when some companies focus on relative risk reduction, rather than quantifying the absolute lifetime risk to an embryo of developing a disease, they are doing their customers a disservice. 

However, some companies are better than others. We founded Herasight to set the standard for what good science looks like in the context of embryo screening. Herasight provides rigorously validated polygenic scores which are the backbone of predicting complex traits in embryos. If a family has one or two embryos and no strong family-history concern, screening may not add much decision value, though there are always exceptions. However, with at least three embryos or a family history of disease, polygenic prediction can be a tool parents welcome when deciding which embryo to implant.  When IVF already requires a choice among embryos, validated genetic risk information can sometimes help families make that choice with more context than morphology, PGT-A, or chance alone.

So the useful question after reading Cox is not whether every company offering genetic tests uses best practices. The question is what a responsible provider must show before asking families to trust that their predictions work. 

Where the article is right

A company in this space called Nucleus recently featured a marketing campaign with the slogan “HAVE YOUR BEST BABY” plastered in New York City subway cars. While the ad is effective at grabbing attention, Herasight showed that the polygenic scores Nucleus was offering at the time were not properly calibrated. Yet many journalists criticized Nucleus’s marketing campaign rather than their science. 

One challenge that Cox’s article in New York Magazine correctly highlights is that not everyone has enough embryos to achieve substantial risk reduction for common diseases. This is mainly a function of the fact that a couple with very few embryos will have less genetic diversity to select from than if they had many embryos. Meaningful risk stratification is still possible, but it is often lower when there are fewer embryos and no family history for a particular disease such as schizophrenia or diabetes. 

Cox also makes another important point: focusing too much on relative-risk between embryos without offering predictors that indicate the absolute lifetime risk of a disease can be misleading. We report both, and focus on absolute risk across the lifetime. A 50% relative reduction can be a tiny absolute change when baseline risk is low. Families deserve the less dramatic number if it is the more honest one, which is precisely what we provide.

Ancestry can be another limitation. Most polygenic-scores have so far been trained on European-ancestry datasets, and performance does not transfer evenly across populations. Herasight's Moore et al. 2025 reports ancestry-specific calibration and shows improvement for African and East Asian populations. That is not the same as saying the problem is solved. It means families should be shown the relevant performance numbers before deciding whether the information is worth adding to their IVF cycle.

Professional-society caution belongs here too. The ACMG points-to-consider statement raised serious questions about clinical utility, evidence, and counseling. Those questions should not be waved away. The answer is better validation, not louder marketing. Moore et al. 2025 tested seventeen disease scores on sibling pairs and found that sixteen held predictive performance within families. Widen et al. 2024 also argued that the original ACMG statement gave an incomplete picture of polygenic prediction. That does not end the debate. It shows the debate has moved from slogans to evidence.

It also helps to separate the genetic tests that often get blurred together. PGT-M (preimplantation genetic testing for monogenic disease) asks whether an embryo inherited a known family variant. PGT-A (preimplantation genetic testing for aneuploidy) asks whether the embryo has the expected chromosome count. PGT-P asks a probability question across many variants for conditions where there is no single yes-or-no gene. Different tests answer different questions, and the evidence standard has to match the decision the family is actually making.

What do genetics companies owe IVF patients?

First, it is important to show how accurate your scores are using within-family validation methods. Embryos from the same IVF cycle can be thought of as potential siblings, so the relevant test is not only whether a score predicts risk among unrelated adults in a population, but between siblings who share the same parents. That is the methodological worry the ACMG statement names, and it is what Moore et al. 2025 set out to test. (More on within-family validation here.)

Outcome tracking is valuable, and any provider should want more of it. But it cannot be the only validation method, because some outcomes take decades. The practical question today is narrower: do the variants and scores that predict disease in adults still rank siblings from the same family in the expected direction? That is the question within-family validation directly answers.

On ancestry, the standard is per-population reporting, not a single average number. A provider that hides ancestry performance behind an averaged statistic is asking families to trust a number they cannot inspect.

Reporting absolute risk across the lifetime is the second principle of good practice. If a family's baseline risk is ordinary, the absolute differences between embryos will usually be small, and the report should say so. If the baseline is elevated by family history or ancestry, the differences can be larger, and the report should say that too. 

Interpretation is the third rule. A multi-page PDF is not counseling. A responsible provider should be able to explain what the absolute risk means for a specific family history, why a score is more or less informative for a specific ancestry background, and when the expected difference between embryos is too small to matter.

And then there is the willingness to say, in public, what PGT-P actually does. The information is meaningful for families who have enough embryos to use it, which is why Herasight does this work. The credential to do it comes from the validation behind the numbers and the honesty about where they apply, not from understating the impact.

A reader who closes Cox's tab can take all of this with her into any provider conversation. Ask whether the provider has tested the scores on actual sibling pairs and published the result. Ask whether the report gives absolute risk with stated assumptions instead of only relative-risk language. Ask whether ancestry performance is reported instead of smoothed over. Ask whether the counselors on the call actually understand PGT-P. And ask whether the provider will tell you, plainly, when the test is unlikely to change your decision. The answers don't have to be perfect. They have to be specific.

On "designer babies"

The phrase "designer babies" is sometimes used to scare people into thinking embryo screening is no different than practices like forced sterilization to weed out “undesirable” people from the population. This is silly. The latter involves government control of decisions, and serious coercion. Selecting an embryo using genetic information is just a way of making the decision a little less random. 

Cox closes his article with a customer who says he would use CRISPR editing if it were available. Herasight has no problem with people editing genes at some point in the future when it is safe, and the genetic architecture of complex traits is well understood.  But it is important to stress that Herasight offers preimplantation genetic testing for polygenic conditions, not gene editing. Gene-edited babies are a different technology and a different debate.

If you want to see what a Herasight report actually looks like, request a sample. If you want to talk through what the current evidence means for your family, reach out to our counselors.