July 27, 2020

As cells grow, so does their morality

CiRA researchers argue that advances in embryonic technology demand a reconsideration of what laboratory creations deserve moral status.

The advancement of science depends on two questions. The first is objective and asks, what can we do? Obviously, something that is impossible cannot be done. The second question is subjective and asks, what should we do? This question requires more delicate thought and is a much stronger indication of our ethics than our knowledge. With embryonic technologies more frequently giving an affirmative answer to the first question, a new essay in EMBO Reports written by the Uehiro Research Division for iPS Cell Ethics and other CiRA researchers considers our answer to the second question by examining the moral status of the resulting entities made from these technologies.

To the human mind, nothing provokes more paradoxical feelings of fascination and preciousness than a human life. The fascination drives a curiosity to understand how one single cell – a fertilized egg – grows into a complex human being of trillions of cells. At the same time, the preciousness holds back our efforts in order to prevent any of the eggs used from going to waste.

When it comes to embryo research, scientists have upheld the “14-day rule” for decades. The rule was made partially in response to Louise Brown, the first IVF baby, who was born in 1978. The rule forbids embryos from being cultured beyond 14 days for research purposes, because the 15th day is when gastrulation begins, or when the embryo can no longer separate to form twins.

Program-Specific Assistant Professor Tsutomu Sawai explains that we need to reassess what laboratory creations should be considered under the 14-day rule.

“The fundamental question we ask is, do the resulting structures have moral status? In vitro culture methods of human embryos and the generation of human embryo-like structures are raising new ethical issues because of their potential of developing a fetus and mature human beings,” he says.

Moral status dictates the 14-day rule. If the entity has moral status, then the 14-day should be applied.

To decide, the potential of the entity, which categories whether the entity can develop into a mature human, is considered. Active and passive potential are entities in which nothing but internal factors or at least one external factor, respectively, are needed for this development. For example, an embryo has active potential, but an unfertilized egg has passive potential.

iPS cells are also entities with passive potential, since reprogramming requires some external influence. However, they are also a good example of how moral status changes with technology. Twenty years ago, no one would believe a blood cell could grow into a human, but iPS cell technology has forced reconsideration, giving any reprogrammable cell passive potential.

“It would be absurd to conclude somatic cells have significant moral status,” says Sawai, but, he added, iPS cells show that it is not so simple to conclude active potential has moral status and passive potential does not. Further, even within passive potential, the essay argues more hierarchies are needed.

Thus, the authors propose advanced passive potential and basic passive potential. Entities that have basic passive potential can only differentiate into specific tissues or cell lineages and therefore need not be burdened by 14-day rule. Judgement for advanced passive potential is not so simple, however.

Advanced passive potential was further broken into categories A and B. Entities that are category A can replicate the whole human embryonic process. They therefore have moral status and should have the 14-day rule applied. As for entities that are advanced passive potential category B, they represent a grey zone that demands more analysis.

“Our suggestion is that the 14-day rule should be applied to even entities which are equivalent to embryo proper, but which lack hypoblast and trophoblast,” says Sawai.

Advances in embryonic technology, Sawai notes, are not only changing our understanding of human development. They are also changing our perspectives on what we define as life.

“The potential to develop into human beings is one of the most contentious issues in stem cell bioethics. With technology changing faster and faster, so too will our conditions for moral status,” he says.

Paper Information

Tsutomu Sawai, Tomohiro Minakawa, Jonathan Pugh, Kyoko Akatsuka, Jun K Yamashita and Misao Fujita (2020). The moral status of human embryo‐like structures: potentiality matters?, EMBO Reports, DOI:

Source: CiRA