Polygenic embryo testing raises ethical concerns beyond disease prevention

For more than four decades, in vitro fertilization (IVF) has helped families have children. Scientists estimate that more than 10 million people worldwide have been born through IVF and related assisted reproductive technologies, according to the International Committee for Monitoring Assisted Reproductive Technologies.

As part of these procedures, prospective parents may choose to genetically test embryos before implantation in the uterus. This process, known as preimplantation genetic testing (PGT), was originally developed to identify serious inherited diseases caused by single errors in the DNA or gene mutations, such as cystic fibrosis or haemophilia, and prevent them from being passed on to the next generation. However, advances in technology have significantly expanded the potential scope of preimplantation genetic testing.

In a new article published in Frontiers in Reproductive Health, Professor Tetsuya Ishii of Hokkaido University examines the emerging use of genomic testing to predict complex traits in embryos, such as intelligence or the risk of developing conditions like diabetes, heart disease, or Alzheimer's disease later in life. As embryo testing moves beyond disease prevention toward the prediction of complex human social characteristics, Ishii argues that stronger oversight and clearer regulations are needed.

Many traits, such as intelligence and physical appearance, as well as the likelihood of developing common diseases like schizophrenia and cancer, are shaped by both our genes and our environment. Unlike monogenic diseases, which result from a mutation in a single gene, polygenic diseases and traits arise from the combined effects of many genes, each contributing subtly, alongside lifestyle and environmental factors.