Source: French to English Tester Published on: 2026-04-29
Source: The Conversation – in French– By Valérie Depadt, Lecturer in Law, Sorbonne Paris Nord University
In France, unlike in other countries, the conditions for using preimplantation diagnosis are very strictly regulated. It cannot be used as a general genetic screening and must target only a known risk. A situation that some would like to see evolve.
While infertility is currently the main reason for resorting to medically assisted procreation (MAP), it is not the only one. In some cases, these techniques are used to prevent the transmission of particularly serious genetic diseases to the child.
For the families concerned, the issue then goes beyond simple conception: it is a matter of giving birth to a child free from the pathology identified in at least one of the parents. In this context, preimplantation diagnosis (PGD), which allows the analysis of the genetic makeup of embryos resulting from fertilizationin vitrobefore their transfer to the uterus – has been authorized in France since 1999.
PGD therefore concerns only a limited number of people. According to the Biomedicine Agency, around 1,000 PGD requests are examined each year, of which about two-thirds are accepted. However, it raises major scientific, ethical, and political questions, all the more acute because the legal frameworks and practices differ significantly from one country to another.
DPI in France: strictly regulated use
PGD involves analyzing one to a few cells taken from the embryo in order to detect a genetic anomaly. Performed simultaneously on several embryos obtained during the same fertilization cycle, it allows excluding from transfer to the uterus embryos carrying the said anomaly.
In France, DPI is authorized when an anomaly responsible for a severely disabling disease, likely to be revealed late or potentially prematurely jeopardizing the vital prognosishas been previously and precisely identified, in one of the parents or one of his immediate ancestors.
However, the law imposes a major restriction regarding the purpose of the test: the diagnosis may have no other purpose than the search for the previously identified genetic anomaly, as well as the identification of means to prevent or treat it. Therefore, PGT is by no means a general genetic screening: it is a targeted test aimed at a known risk.
This legal framework reflects a medical conception of PGD: it is an alternative to a medical termination of pregnancy when the risk of disease is high. Thus, the procedure is covered by Health Insurance up to four IVF cycles. Due to the high level of technical expertise required and a desire for centralization, only five specialized centers have authorization: Paris, Strasbourg, Montpellier, Nantes, and Grenoble.
The terms of French law also explain the technological limitations observed in our country. In France, given that only the search for the pathology subject to diagnosis is authorized, the use of modern sequencing methods, called “pangenomic” (because they allow sequencing the entire genome), remains marginal.
It is different abroad, where such techniques are widely used.
Abroad: the development of screening for chromosomal abnormalities
In several countries, notably in the United States, the United Kingdom, and Spain, advances in genetic sequencing have led to a different use of preimplantation diagnosis. It is used for the general screening of chromosomal abnormalities in the embryo.
This type of PGT is called PGT-A, for aneuploidies. Aneuploidies are abnormalities in the number of chromosomes, such as trisomies or monosomies (among the most well-known examples of aneuploidy is Down syndrome, which is characterized by the presence of an extra chromosome 21)eA pair of chromosomes).
PGD-A therefore no longer consists – or no longer solely consists – in searching for an identified familial genetic disease. It involves the examination of the entire set of chromosomes of embryos produced by fertilization.in vitrobefore transferring them into the uterus, in order to identify those that have a normal chromosomal number. These embryos are assumed to have better chances of implantation and live birth.
Abroad, this technique is widely offered in certain clinics, particularly in the private sector, sometimes beyond strict medical indications. In some European countries, in the United States, or in Canada, where PGT-A is presented as a factor in increasing the chances of success,it is used in a significant portion of IVF cycles.
Why is this practice prohibited in France?
This situation is explained by the desire to limit any extension of the diagnosis towards a broader embryonic selection, which is seen as likely to open the way to eugenic abuses.
However, some French ethical bodies have recently helped to revive the debate by recommending that the medical interest of these techniques be evaluated within a strictly regulated framework.
The National Consultative Ethics Committee for Life Sciences and Health (CCNE), in itsopinion 129 of 2017, was in favor of authorizing the search for aneuploidies during fertilizationsin vitro, for couples using PGD and certain infertile couples.
For the Biomedicine Agency, it is also appropriate to question the consequences of the possibility of sequencing the entire genome,including in the field of prenatal diagnosis.
Unfortunately, at the present time, the necessary data to make a decision is still lacking.
The DPI-AÂ: a scientific benefit still debated
The DPI-A is based on a biologically coherent hypothesis: chromosomal abnormalities beingfrequent in human embryos(At the level of30 to 60% of embryos systematically studied during a pre-implantation diagnosis, their identification could theoretically improve IVF outcomes, reduce the risk of implantation failure, miscarriage, medical termination of pregnancy, or the birth of a child affected by a serious genetic disease.
However, the scientific data appears less convincing than expected regarding the anticipated benefits.
Recall that an IVF cycle corresponds to a complete attempt, including ovarian stimulation, oocyte retrieval, and embryo transfer(s), with several transfers possibly originating from the same cycle. In France, the live birth rate is approximately 25% per initiated cycle. In practice, patients undergo on average two to three cycles to achieve a live birth, thechances increasing cumulatively with the number of attempts. The distinction between rate per transfer and rate per initiated cycle is essential, the observed benefit of DPI-A mainly relating to the first indicator.
Specifically, during in vitro fertilization (IVF), several oocytes are fertilized in the laboratory to obtain a limited number of embryos (often between five and ten). Without PGT-A, one or more embryos are selected based on morphological criteria and transferred, with the others possibly being frozen. With PGT-A, each embryo is biopsied and only those considered euploid (having the correct number of chromosomes) are kept for transfer.
This selection leads tode factoa decrease in the number of available embryos. Data from IVF cohorts show that on average 30 to 60% of embryos at the blastocyst stage (five to six days of development) are aneuploid, a proportion that increases with maternal age. For example, in a patient obtaining eight blastocysts, PGT-A may lead to identifying only two to three euploid embryos, or even none depending on age, thereby reducing transfer possibilities.
The systematic exclusion of mosaic embryos, that is to say embryos containing both euploid and aneuploid cells, can exacerbate this reduction, even though live births of healthy children have been reported after the transfer of such embryos.
The consequences of this selection are multiple: a decrease in the number of transfers possible per cycle, an increase in the number of cycles necessary to achieve a pregnancy, and the risk of losing potentially viable embryos.
The studies conducted show to a large extent aincrease in pregnancy rates by embryo transfer in certain contexts, such as implantation failures or recurrent miscarriages.
However, this does not seem to be systematically the case for the live birth rate per cycle started, which is nonetheless the most relevant indicator for couples. PGD-A could even lead to abirth rate decreased among women under 40 years old.
How can these results be explained?
Several biological limitations explain these contrasting results. Embryonic biopsy is based on the analysis of a limited number of cells, which can lead to interpretation errors due to a representativeness problem.
In the presence of embryonic mosaicism, in other words when the embryo contains both normal cells and aneuploid cells, the cells taken for analysis may not reflect the chromosomal constitution of the entire embryo, leading todiscordant results or classification errors.
Moreover, there is sometimes a capacity for self-correction. This phenomenon constitutes a major limiting factor of NGS (Next-Generation Sequencing). Furthermore, variability in sampling conditions and the analytical limitations of sequencing techniques can contribute to false positives or false negatives, particularly in the detection of mosaicism.
Finally, not all miscarriages are linked to chromosomal abnormalities, which mechanically limits the potential impact of aneuploidy screening on live birth rates.
In view of these uncertainties, the international scholarly societies, in particularEuropean(EHRE) andAmerican, remain cautious anddo not recommend the systematic use of ICSIin routine clinical practice for all couples undergoing IVF. There could be a benefit for certain subgroups of patients, notably the older ones, or those who have experienced multiple spontaneous miscarriages.
The current limits of knowledge highlight the need for rigorous studies, also including medico-economic aspects, in order to assess the real interest of DPI-A according to different patient populations and clinical contexts. Indeed, theperforming a double ICSI doubles the cost of a conventional IVF.
To fill these gaps, the National Agency for the Safety of Medicines and Health Products (ANSM) had authorized in 2021 the Assistance Publique – Hôpitaux de Paris (AP-HP) to implement a clinical trial (DEVIT trial) in order to collect data on these issues. The objective of this study was to evaluate its benefits and risks.
But on February 7, 2024, the Administrative Court of Montreuil (Administrative Court of Montreuil, 8eChamber, February 7, 2024, noTo 2206833) seized by theJerome Lejeune Conservative Foundation, annulled the ANSM authorization, recalling the legal prohibition of DPI-A, including at the research stage.
By a decision of the10 July 2025, the Paris Administrative Court of Appeal has confirmed the decision of the Administrative Tribunal.
The study is therefore halted, while the objective evaluation of benefits and risks precisely requires methodologically sound work.
The DPI-AÂ: a particularly polarized French debate
In France, the issue of DPI-A sparks a particularly divisive debate.
Some patient associations, such as theBAMPÂ collective!, denounce an inconsistency: screening for Down syndrome is widely offered during pregnancy, with the possibility of medical termination in case of an anomaly, while pre-implantation screening remains prohibited.
Isn’t the risk of eugenics lower when it comes to selecting viable embryos than in the systematization of a proposal to detect trisomy 21 in the fetus, a few months after the beginning of the pregnancy?
This situation de facto creates inequalities of access, since only couples with the necessary financial resources have the choice to go abroad.
On the contrary, opponents, like theJérôme-Lejeune Foundation, consider that the extension of PGT to chromosomal screening could reinforce an embryonic selection logic and would raise major ethical questions, particularly regarding disability.
Put science back at the heart of the discussion
In this context, the debate cannot be easily reduced to a contrast between a supposedly neutral scientific assessment and positions linked to ethical and societal considerations.
The available scientific data concerning PGS-A remain indeed debated: while some studies suggest a benefit in targeted indications (repeated implantation failures, recurrent miscarriages), others highlight the lack of significant improvement in live birth rates for all patients undergoing ART, as well as the limitations related to embryonic mosaicism, the representativeness of the biopsy, and the variability of practices.
The scientific assessment itself is therefore marked by uncertainties, methodological choices, and divergent interpretations.
At the same time, the use of PGT-A raises issues that go beyond the biomedical field alone, particularly concerning the representation of disability, embryonic selection, equity of access to healthcare, and the purposes assigned to reproductive medicine. These aspects involve collective choices and ethical frameworks, which cannot be resolved by scientific data alone.
The absence of a legal framework for research on AI-powered PMD in France has paradoxically hindered the production of national scientific data, as evidenced by the decision of the Montreuil administrative court.
France conceives the evolution of authorized biomedical techniques only in compliance with the great principles concerning the human body, as set forth in theCivil Code at articles 16 and following, excluding any commercial consideration.
The history of PGT illustrates the ongoing tension between biomedical progress, patient expectations, and ethical concerns. PGT-A now embodies significant hopes for improving IVF outcomes, but also worries regarding its societal implications.
In this context, the issue is perhaps less about immediately deciding “for” or “against” than about consolidating the available knowledge. Depoliticizing the debate, better informing the public, supporting research, and clarifying uncertainties appear to be essential conditions for guiding future decisions in public health.
In a field marked by the rapid pace of innovations and the scale of ethical issues, the quality of scientific data must play a determining role in the way our society defines and will define collective choices to come.
Marjolaine Willems is a member of the French Society of Preimplantation Diagnosis (SFDPI). She has received funding from the Biomedicine Agency.
Valérie Depadt does not work for, advise, own shares in, receive funds from any organization that could benefit from this article, and has declared no other affiliation than her research organization.
–ref. Preimplantation diagnosis and chromosomal abnormalities: the scientific and ethical challenges of PGD-A –https://theconversation.com/preimplantation-diagnostic-and-chromosomal-abnormalities-the-scientific-and-ethical-issues-of-PGD-273039