Towards high-tech embryo selection: Nucleus Embryo or the unlimited choice of the perfect child

According to its designer, Kian Sadeghi, this proposal is “guided on the principle of responsible use of modern genomic science and reproductive freedom.” However, such embryo selection calls into question the dignity accorded to the embryo and raises significant risks associated with the use of biotechnology in the conception of children.

From preventive medicine to genetic selection of embryos 

Nucleus Embryo offers to analyse almost all of the DNA of embryos conceived through IVF, or only common genetic markers if the parents have not opted for total genome analysis. If they want more precision, parents are invited to sequence their own genome via Nucleus Family, another Genomics service that screens for more than 900 hereditary diseases that may affect their children. Nucleus Embryo's technology uses a series of tools that identify rare or potentially pathogenic genetic variants. Even if no pathogenic variants are detected, Nucleus Embryo also provides polygenic scores for common diseases and characteristics such as Alzheimer's disease, certain cancers such as breast cancer, type 2 diabetes, and heart disease. 

Polygenic scores are calculated by taking into account the combined impact of several thousand genetic variants to determine a genetic predisposition to a complex disease. However, many other non-genetic factors such as family history, lifestyle, and environment also play a role in the development of common chronic diseases, which means that Nucleus' predictions must be treated with caution. 

The use of this tool, originally designed for preventive medicine, raises questions in this context. In this case, the aim is not to prevent the onset of a disease in order to provide better care for the patient, but to make a selection among healthy embryos to ensure that the best ones are implanted. According to its designer, “people have the right to genetically optimize their children.”  

Towards technological eugenics 

In this context, questions arise about the limits of this search for the best embryo. On its website, Nucleus states that “the nature of most genetic predictions is uncertain.” Avoiding potential diseases in one's child in adulthood and thus allowing parents to “make informed choices for individual health and that of future generations” actually involves destroying healthy embryos. Furthermore, as Jason Thacker, assistant professor of philosophy and ethics interviewed by Newsweek, points out, analysing and selecting certain embryos over others on the basis of characteristics and risks is no longer about preventing future generations from suffering, but about decreeing that some human lives are more valuable than others. 

Under the guise of promoting good health and reproductive freedom for parents, this proposal paves the way for liberal eugenics, which will soon have no limits other than technological progress. According to the Nucleus website, more and more parents are adopting new technologies to have “healthy and fulfilled” children. This mentality, encouraged by embryo screening techniques, would lead “four out of ten parents” in the United States to use genetic optimization as an additional tool to “increase their child's chances of getting into a top university.” 

The use of artificial reproduction techniques, particularly IVF, could well become widespread among couples who are not infertile but who want to optimize their choice of embryos if these technologies become more accessible in the future. 

From therapy to enhancement, where will the line be drawn?  

The range of research into genetic predispositions to diseases and traits is so broad that one wonders where the design of the desired child will end. Since this is no longer a question of treatment but of selection based on the best genetic dispositions, a first step in the enhancement of future generations has already been taken. 

Designing a child who would be as unlikely as possible to contract diseases throughout their life and who would therefore have a longer life expectancy is the transhumanist dream of a performance-oriented society where accepting illness and imperfection would seem senseless. This is the vision held by certain thinkers such as Julian Savulescu, an Australian philosopher and bioethicist, who advocates the use of artificial reproduction to select embryos that will have the best possible life, i.e., without disease or disability. According to this logic, since it is possible to choose the best embryo, leaving it up to the lottery of nature would be a moral failing, and selecting embryos would therefore be an act of “reproductive charity.” 

It remains to be seen what the psychological impact will be on children thus conceived, selected, and required, even before birth, to meet such performance criteria. 

Sources: Nucleus Genomics website, Newsweek (04-07-2025) and Bioethics Observatory (26-06-2025)