Human Embryo Research Beyond 14 Days? International Perspectives

Five  years ago, independent research teams in the United States and the United Kingdom succeeded in cultivating human embryos in the laboratory for 12-to-13 days – longer than ever before. They could have continued their research but didn’t. They stopped because of the broad international consensus that such research should not be permitted beyond 14 days (often referred to as the 14-day rule). And, in the U.K. stopping would have been further incentivized by the legal prohibition on such research.

This technical achievement sparked an ethical debate that had been simmering for some time. Following on this research scientists were at pains to highlight the many potential benefits of human embryo research beyond 14-days including increased understanding of human development, the causes of recurring miscarriage, and congenital anomalies.

In late May these scientists, and no doubt others waiting in the wings, got their wish. The International Society for Stem Cell Research (ISSCR) updated its 2016 guidelines, eliminating the previous prohibition on human embryo research beyond 14-days. The task force responsible for the 2021 update included a...