In France, since 2021, research carried out on the human embryo can extend until the fourteenth day of development. Is this delay ethically legitimate or does it hamper the search for valuable knowledge for reproductive health? Are there alternatives to continue to progress in this area?
An article to be found in the Inserm magazine n°55
This summer, two research teams cultured mouse embryo models in vitro for more than 8 days, nearly half the natural gestation length of rodents. Such advances raise questions about the current framework for research carried out on the human embryo. Authorized and supervised since 2013 in France, these can, since 2021, relate to the development of embryonic cells during their first 14 days, against 7 previously. Is this delay ethically legitimate or does it hamper the search for valuable knowledge for reproductive health? Do animal models allow us to know as much as the human embryo? And what about research on cellular models created to study a specific aspect of embryonic development: should they be limited by the same ethical considerations? At a time when the projects are under recurrent attack from an associative foundation, a clinical researcher and two members of the Inserm ethics committee are analyzing the situation.
Julie Steffann’s analysis
Very little is known about the physiology of early human embryonic development, while two thirds of embryos do not reach the fetal state, whether in vitro fertilization (IVF) or, no doubt, in vivo, and less than a third of couples have a child following IVF. Today, to compensate for these failures, we are increasing the number of attempts; it would be better to try to understand! Admittedly, animal models and human embryonic models help to formulate hypotheses on the causes of these failures, but they have their limits. For example, the majority of human embryos have chromosomal abnormalities harmful to their development, unlike those of mice. For what ? The law now restricts our research to the first 14 days of the embryo, on the grounds that its nervous system is then formed. However, it is strange to prohibit research, including with strict ethical protocols, in the time window where abnormalities of the nervous, renal and cardiac systems appear. Some believe they are fighting against eugenics in this way, but these fears stem from ideological fantasy: it is extremely difficult to keep embryos alive beyond 6 days! Is it the fear that the embryo will be demystified by a Petri dish? We need a law which regulates instead of prohibiting, and above all a political will which encourages and supports research on the embryo. In a context of public reluctance, our projects are fragile and under attack. However, they are 100% funded by associations, which proves that they raise real expectations within society. One day, we may cure embryos conceived by IVF and affected by genetic disease: new genome editing techniques could correct these defective genes. But upstream, research is essential!
Julie Steffann is a researcher at the Imagine Institute (unit 1163 Inserm/Paris-Cité University), head of a medical unit genomics rare diseases at the Necker-Enfants Malades Hospital, Paris.
Pierre Jouannet’s analysis
Today, research on the human embryo is made very difficult by the ambiguities of the law and the interpretations made of it. The legislator does not distinguish the embryo – which by its inclusion in a parental project is a potential person – from “embryonic models for scientific use” (MEUS). These models are created in vitro only to answer major scientific and medical questions. To confuse them with embryos, as the law does, is to handicap research. Thus, MEUS can be created from stem cells to study the cellular and tissue differentiations that lead to organ formation and embryonic morphogenesis. A better knowledge of this stage of the first weeks of life is essential, from a fundamental point of view, to explain the origin of miscarriages and malformations of the child, but also of pathologies which can appear well after the birth. birth. Unfortunately, this research is impossible in France, whereas no transfer of MEUS into the uterus could be envisaged given that they would be incapable of implanting themselves in the uterine mucosa. The regulatory framework for research should better distinguish between those carried out on embryos likely to become people and those involving embryonic models whose purpose is to improve medical and scientific knowledge. This framework should enable researchers to carry out their work in an ethically responsible manner with the respect due to the human person and to the embryo itself. And to avoid them being permanently confronted with the actions of those who wish to prevent in France, by all means and whatever the cost, any research relating to the human embryo. To better fight against sterility, to improve our knowledge of all ages of human life, it is urgent to know the embryo better.
Pierre Jouannet is professor emeritus, specialist in reproductive biology, member of the Inserm ethics committee.
Bernard Baertschi’s analysis
In the name of what ethical issues does research on the human embryo deserve a separate legislative framework? In France, consent can only be given for an embryo devoid of parental project, it must be informed and can be withdrawn within three months. This framework is not subject to debate, but the “embryonic models for scientific use” (MEUS) could raise the question: would specific consent be required to use an individual’s stem cells? Who do they belong to? However, this point also revives the question of the status of the embryo. Where does the respect some give him come from? In our societies, we attribute moral status to individuals possessing traits that we value. What are those of the embryo? He is not endowed with reason. The closer he approaches birth, the more human capacities he acquires, which may justify assigning him a gradual moral status. Is he, however, from the outset a “potential human person”? Perhaps in the sense that everyone is a potential leader: if the conditions are right, they can become one. But the MEUS and the embryos studied in research will never be people since it is forbidden to implant them. Only the parental project justifies treating the embryo as a person in the making. Therefore, why restrict research on the embryo to its first 14 days of life, on the model of the Warnock report which, in 1984, established the ethical framework for research on the human embryo in the United Kingdom? It is because, from this limit, an embryo split in two no longer splits, it dies. So, if it were necessary to say when the individual begins, it would be there. However, only an individual is likely to be legally protected. However, having an organic unity is not enough to be a human person.
Bernard Baertschi is professor of philosophy at the University of Geneva, member of the Inserm ethics committee.
🔎 To find out more about research on embryos and embryonic models for scientific use (MEUS), read the note from the Embryon and development think tank of the Inserm ethics committee.