Hokkaido University Ethicist Warns of Regulatory Gaps as Embryo Screening Shifts Toward Intelligence and Complex Trait Prediction

Professor Tetsuya Ishii warns that embryo testing for intelligence and complex traits lacks regulation and risks creating unrealistic parental expectations.

By: AXL Media

Published: Apr 1, 2026, 7:57 AM EDT

Source: Information for this report was sourced from Hokkaido University

The Evolution of Assisted Reproductive Technology

For more than forty years, in vitro fertilization has served as a cornerstone of modern reproductive medicine, facilitating the births of an estimated 10 million individuals globally. Traditionally, the genetic screening of these embryos was confined to identifying monogenic disorders, which are severe conditions like cystic fibrosis or hemophilia caused by a single DNA error. However, a significant shift is occurring as the scope of preimplantation genetic testing expands. New genomic tools now allow prospective parents to screen for polygenic traits, which involve the subtle interactions of hundreds of different genes, fundamentally altering the purpose of embryonic selection.

The Complexity of Polygenic Scoring Systems

Unlike inherited single-gene mutations, complex characteristics such as the risk for heart disease, schizophrenia, or even cognitive aptitude are shaped by a combination of genetics and environmental factors. Polygenic scores provide a statistical estimate of an individual's genetic tendency toward a specific trait, yet Professor Tetsuya Ishii of Hokkaido University warns that these predictions remain highly uncertain. Because these scores do not account for lifestyle, upbringing, or environmental influences, they cannot guarantee that a child will actually manifest the predicted characteristics. This scientific gap creates a significant risk of misleading parents who may hold unrealistic expectations for their future offspring.

Global Divergence in Bioethical Regulation

The regulatory landscape for polygenic embryo screening is characterized by a lack of international consensus, creating a patchwork of legal standards. In the United States, these services have been commercially available since 2019, with some fertility clinics offering them as a routine part of the IVF process. Conversely, several European nations, including Germany and Italy, maintain strict prohibitions against any screening not directly related to preventing serious genetic diseases. The United Kingdom has similarly declined to permit the use of polygenic scores for selection, reflecting a cautious approach that prioritizes ethical stability over technological expansion.