[BDSP. Notice produite par INIST-CNRS 1LR0xxoc. Diffusion soumise à autorisation]. Down's Syndrome prenatal diagnostic and screening techniques have spread widely in France over the last 30 years and are now part of the routine clinical practice of prenatal care. These techniques, which originated in the field of genetics, ultrasonography and biochemistry, were the first to provide the possibility of choosing the features of the foetus, or at least to reject some of its characteristics. They lead to new norms of healthy foetuses and a progressive acceptance of medical abortions. The aim of this paper is to understand how the use of these tests has been generalised in France despite scientific controversies about their risks and ethical questioning about a potential renewal of eugenics. It analyses the representations of public needs that have been articulated by key players in the scientific and medical fields. This research explores political and administrative decision making processes to understand how progressively widening public access to prenatal testing has been organised and funded. The results highlight the scientific and political role of biomedical researchers, the forms of involvement of health authorities and politicians, and the passive participation of the vast majority of the users. The paper also examines the characteristics of the French health system that facilitated the generalised use of the technology.