[The problem of sex chromosome aneuploidy in genetic counseling using amniocentesis]

The identification of chromosomal alterations remains, undeniably, one of the major objectives of prenatal diagnosis by amniocentesis. A series of 500 cases personally tested by the authors confirms entirely the validity of the principal indication for, and the benefit of, this modern method for the intrauterine detection and prevention of many severe congenital chromosome defects. In our experience, the cases of genetic counselling following detection of sex chromosome anomalies have proven to be particularly difficult. In two of three situations where such a diagnosis was revealed (an XYY and XXY fetus), after hours of discussion and reflection, the parents opted to pursue the pregnancies to term. In the third case (an XYY fetus), an abortion was requested. Certain aspects of these decisions are discussed and the opinions of participants solicited.