Polygenic embryo testing is raising new ethical questions as its use expands beyond preventing inherited diseases, according to a Mar. 31 article published in Frontiers in Reproductive Health by Professor Tetsuya Ishii of Hokkaido University.
The development matters because advances in genetic screening now allow prospective parents to select embryos based on complex traits such as intelligence or risk for conditions like diabetes and heart disease, not just single-gene disorders. This shift could have significant implications for families and society at large.
Preimplantation genetic testing (PGT) was originally used to identify serious inherited diseases caused by single gene mutations, such as cystic fibrosis or haemophilia. However, recent technological progress has enabled the prediction of polygenic traits—those influenced by many genes and environmental factors—through statistical tools called polygenic scores. These advancements mean that PGT can now be used not only for monogenic diseases but also for assessing an embryo's likelihood of developing common conditions later in life.
"However, predicting complex traits remains highly uncertain. Polygenic scores attempt to predict these complex traits using only an embryo's genetic variants and data from large genetic studies, without accounting for environmental influences," explains Ishii.
Regulation varies widely around the world. In the United States, commercial polygenic embryo screening has been available since 2019, with some clinics offering it routinely. Surveys suggest that while many Americans support reducing disease risk through these methods, some are also open to using them for non-medical characteristics. By contrast, countries like Germany and Italy restrict embryo testing to preventing serious genetic diseases; the United Kingdom does not currently permit polygenic scoring for selection at all.
Ethical concerns include unrealistic expectations about children’s future abilities or health based on uncertain predictions. "Because of environmental influences, parental behavior, the child's autonomy, and many other factors, the use of polygenic scores cannot guarantee that a child will develop the predicted trait," says Ishii. There are also worries about stigmatization of certain traits and fears that such technologies could lead back toward eugenics-like thinking.
Ishii argues that policymakers should introduce precautionary regulations while educating the public about what current genetic science can—and cannot—reliably predict regarding future children’s outcomes.
