The 14-day limit for cultivating human embryos in the lab should be extended to advance knowledge, according to recommendations made Wednesday by stem cell experts working to establish an international scientific framework for this type of research. In some countries, this research is not regulated by law, and even when it is, it occurs in the absence of international legislative coordination. Thus, researchers from around the world rely on recommendations from the International Society for Stem Cell Research in addition to their local laws.
The International Society for Stem Cell Research issued its updated guidelines on Wednesday for the first time since 2016. These recommendations cover a broad range of research with significant ethical implications, from implanting human cells into living animals to genome editing and the formation of organs from stem cells. This field is becoming closer to science fiction and causes fear among the general public.
Robin Lovell-Badge, head of the group of 45 experts behind the new recommendations from the Francis Crick Institute in London, explained that "the most significant proposed change may be the exemption from the 14-day rule, the period during which healthy human embryos must be cultured in the lab."
This committee of experts does not propose a new deadline, but recommends the possibility of exceeding 14 days based on proven scientific reasons and public consultation in the country where the concerned research is conducted. Lovell-Badge noted in a comment published in the medical journal Nature that the 14-day period after fertilization, at the end of which embryos must be destroyed, "is applied under the laws of dozens of countries, including the United Kingdom and Australia."
In France, the law does not specify a maximum limit, but in practice, it has been set at seven days. The government wishes to officially extend it to 14 days as part of a bioethics law currently being discussed in Parliament. However, for the scientists of the International Society for Stem Cell Research, this threshold is outdated.
Lovell-Badge explained, "When this limit was proposed nearly 40 years ago, no one was able to culture human embryos beyond five days or a little more. But today, this maximum period prevents us from studying a critical period of embryonic development that requires between 14 and 28 days."
According to him, the 14-day period comes just before "the first signs of central nervous system formation." Thus, "we know very little about what happens inside the embryo" during the period following the fourteen days, which is considered the "black box" of human development.
Lovell-Badge stated, "From an ethical perspective, we can consider that we need a better understanding of this period of human development due to its significance," arguing that this contributes to enhancing knowledge about abortion cases and physical deformities in embryos.
This type of research has made significant progress in recent years. In March, two teams of researchers announced they had produced early human embryonic structures in hopes of learning more about the early stages of development. These experimental structures correspond to blastocysts, the first stage of embryo formation, occurring about five days after fertilization of the egg by sperm.
These models, known as "blastoids," which cannot continue to develop like natural embryos, are not subject to the 14-day rule. However, this maximum limit hinders the verification that what happens inside these experimental models corresponds to what occurs inside real embryos, according to researchers.
