For the past 40 years, this voluntary directive has served as an important stop sign for embryonic research. This made it clear to the public that scientists would not grow babies in the lab. For the researchers, this clarified the research they could do.
Now, however, a key scientific body is set to remove the 14-day limit. The action would come at a time when scientists are making remarkable progress in growing embryonic cells and watching them develop. Researchers, for example, can now create embryo-like structures even from stem cells, and some hope to follow them. synthetic embryo models well beyond the old two week line.
By allowing both normal and artificial embryos to continue to develop after two weeks, ending the self-imposed limit could trigger some impressive but ethically charged new experiments on extending human development outside of life. ‘uterus.
The International Society for Stem Cell Research has prepared draft recommendations to move this research out of a category of “prohibited” scientific activities for a class of research that can be allowed after ethical review and depending on national regulations, according to several people familiar with its thinking.
A spokesperson for the ISSRC, an influential professional society with 4,000 members, declined to comment on the change, saying its new guidelines would be released this spring.
Because embryo research does not receive federal funding in the United States, and laws differ widely around the world, the ISSRC has assumed disproportionate importance as a de facto ethics regulator in the field. The rules of society are invoked by universities and by scientific journals to determine what types of research they can publish.
The existing ISSCR guidelines, published in 2016, are updated due to a wave of new research that crosses borders. For example, some laboratories attempt to create human-animal chimeras through experiments, including mix human cells into monkey embryos. Researchers also continue to explore genetic modification of human embryos, using gene editing tools like CRISPR.
Many laboratories are also working on realistic artificial models of human embryos built from stem cells. For example, last week Zernicka-Goetz published a preprint describing how his lab caused the stem cells to self-assemble into a version of a human blastocyst, as a one week old embryo is known.
While scientists are keen to explore whether such lab-created mimicry can be taken further, the 14-day rule stands in the way. In many cases, model embryos must also be destroyed before the end of two weeks.
The 14 day limit was born after the birth of the first test tube babies in the 1970s. “It was, ‘Oh, we can create human embryos outside the body – we need rules,’ says Josephine Johnston, a researcher at the Hastings Center, a non-profit bioethics organization. “It was a political decision to show the public that there is a framework for this research, that we don’t grow babies in the lab.”
The rule went unchallenged for many years. Partly that was because scientists couldn’t grow embryos for longer than four or five days anyway, which was enough for in vitro fertilization.
Tetsuya Ishii, a bioethics and law researcher at the University of Hokkaido, says some countries, including Japan, have put the 14-day limit in law. Others, like Germany, completely ban embryo research. This means that a change in guideline could do the most to open up new fields of competition between countries without federal restrictions, especially among scientists from the United States and China.
Scientists are motivated to grow embryos for longer in order to study – and potentially manipulate – the developmental process. But such techniques raise the possibility of one day gestating animals outside the womb until birth, a concept called ectogenesis.
According to Ishii, new experiments “could spark debates about abortion,” especially if researchers develop human embryos to the point where they take on recognizable features like a head, beating heart cells, or the beginning of limbs.
Under the Trump administration, embryologists tried to keep a low profile for the surprising technical progress in their laboratories. Fears of a presidential tweet or government action to obstruct research have helped keep discussion of changing the 14-day rule in the background. For example, the ISSRC guidelines were complete in December, according to one person, but they have yet to be released.