Abstract

This article studies how the development of diagnostic techniques defines the norm, the «normal» and the «abnormal», and influences decisions of pregnant women as well as of health professionals. Following a brief reconstruction of the historical evolution of prenatal diagnostics, this text analyses a particular anomaly: sex chromosome aneuploidy (SCA). Although some cases of SCA may present severe deficiencies, the great majority of children who have an abnormal number of sex chromosomes experience relatively minor problems. In many cases, diagnosis of SCA only surfaces during the person's adolescence, or remains undiagnosed. The borderline characteristic of most SCA, and the difficulty of predicting how it may affect a person's life, makes decisions about continuation of pregnancy following diagnosis of this condition especially difficult. Hence, the prenatal diagnosis of SCA reveals the construction of the «abnormal fetus» and the «risk of having a disabled child» as a techno-social phenomenon which emerges over time through the complex intertwining of new medical technologies, changes in the organization of medical work, public health considerations and shifting legal frameworks.