Expecting parents who have reached the IVF stage suddenly find themselves faced with a new set of decisions. Beyond selecting which embryo to transfer, clinics now offer genetic screens that promise to reveal a range of health outcomes, even traits such as height or intelligence. The promise of a healthier, perhaps even “better,” child can feel compelling, yet the technology is still evolving and carries hidden complexities. Below we unpack the two main kinds of tests, explain the statistics they quote, and explore the broader ethical terrain that accompanies these choices.
What the available tests actually do
The first, more established option is PGT-A (pre-implantation genetic testing for aneuploidy). It entered clinical practice in the 1990s and can identify chromosomal abnormalities such as trisomy 21, the cause of Down syndrome, while also revealing the sex of each embryo. Importantly, sex determination does not guarantee a child’s gender identity later in life—a point often missed in marketing materials. The second, newer suite of services is polygenic testing. Companies analyze thousands of genetic markers to estimate an embryo’s susceptibility to complex conditions like type-2 diabetes, breast cancer, and even psychiatric disorders. Some firms also market “enhancement” scores, claiming they can predict traits such as height or IQ.
How the numbers can mislead
Statistical genetics is notoriously subtle, and the way risk reductions are presented can create a false sense of certainty. As statistical geneticist Sasha Gusev notes, a claim that a test lowers the absolute risk of type-2 diabetes by 12 % does not mean the child’s chance of ever developing the disease drops by that amount. In practice, it may simply shift the predicted onset from childhood to a later decade, or move the child from a high-risk to a moderate-risk bracket. The same logic applies to other conditions, including breast cancer. Gusev warns that “typical risk reduction estimates tend to exploit statistical assumptions to overstate their benefits and lead to confusion.”
Ethical and social ramifications
Beyond the scientific nuances, several moral concerns arise. Psychologist Eric Turkheimer points out that polygenic scores for mental health are still imprecise, and that many psychiatric conditions exist on a continuum rather than as binary “diseases.” He asks, “Sure, it would be nice if no one ever got depressed, but what would that actually mean?” Removing mild forms of anxiety might also erase traits linked to creativity, as the author of the original column observes about her own experience.
A related concept is pleiotropy—the fact that a single gene can influence multiple traits. Selecting against a gene associated with higher depression risk could unintentionally diminish other, perhaps desirable, characteristics. Because our understanding of these connections is incomplete, large-scale embryo selection could produce unforeseen trade-offs.
Financial barriers intensify the dilemma. Companies such as Orchid charge roughly $2,500 per embryo screened; testing ten embryos can total $25,000. This price tag raises concerns about widening socioeconomic disparities, where wealthier families could afford what some view as a genetic advantage, while others are excluded. Moreover, as the technology becomes more common, social pressure may emerge, implicitly coercing parents to use it to keep their children competitive.
Philosophical voices like Julian Savulescu argue that parents have a “moral obligation” to give their children the best possible start, a stance that commercial providers readily adopt. Yet utilitarian reasoning that focuses solely on maximizing health or intelligence can eclipse other values—cultural diversity, individual autonomy, and the acceptance of natural variation. Nobel laureate Herbert Simon’s concept of “satisficing”—choosing an option that is good enough rather than optimal—offers a pragmatic alternative. For instance, screening for severe, well-characterized conditions such as Tay-Sachs or high-penetrance BRCA mutations is widely considered reasonable, while opting for enhancement scores is far more contentious.
Ultimately, each family must balance scientific information, personal values, and financial reality. Parents should beware of language that frames non-use as negligence—questions like “What if you could have stopped it… but chose not to?” exploit fear rather than present choice. By critically assessing the data, considering the limits of prediction, and reflecting on what a “good enough” life looks like for them, prospective parents can make a decision that aligns with both their hopes and the broader ethical landscape.
