► This would improve knowledge
Hervé chneiweiss, neurobiologist, president of the ethics committee of Inserm (National Institute for Health and Medical Research)
The choice to set the period beyond which researchers cannot cultivate an embryo at 14 days is a totally artificial choice. This delay stems from an international consensus established in the 1980s, which considers that at 14 days appears in the embryo the emergence of a midline which, later, will become the central nervous system. The fear was that the embryo would suffer, but we have known since that the cells, at 14 days, cannot convey the slightest sensitivity. These 14 days are therefore not biologically justified.
All studies on the embryo have the interest of understanding the early stages of development. However, cell differentiation allowing the creation of organs begins at 14 days. Being able to go further, by pushing up to 21 days for example, would make it possible to dig deeper into this outline of organogenesis. The techniques allow it, should it be authorized? I believe that under well-supervised conditions, we could be much more flexible. There are control institutions which it would be good to trust. And if researchers really propose projects deserving of cultures for more than 14 days, an ethical weighing between the main philosophical principles and the contributions of this research would allow derogations.
► The current deadline already allows progress
Philip Berta, deputy (MoDem) and geneticist, former co-rapporteur of the bioethics bill
The bioethics law of August 2021 sets the deadline beyond which researchers must destroy supernumerary embryos cultured in vitro at 14 days. But you have to know where you are starting from. Until then, there was no precise legislation on the duration of culture of these embryos. The seven-day limit that was applied by the teams was more an implicit consensus than a real legislative framework. This delay can be explained in particular because a few years ago, we were technically unable to go beyond that.
It is now possible and the bioethics law, which for me is a failure on many other points, has at least succeeded in enshrining this in the texts. Before wanting to go further and push this deadline to 21 days, as some scientists are calling for, let’s already consider the advances in research made possible by these seven additional days. Seven additional days is additional information to better understand embryonic development, to better understand the processes that make an embryo succeed in implanting itself in the uterus or not. This delay is a balanced delay. The 14-day limit is retained in almost all other countries. For the moment, it seems reasonable to me to model ourselves on this majority situation.