[Medicopsychosocial syndrome of polygonosomies (XXX, XXY, XYY, syndromes etc...)].

This is an attempt to describe a common syndrom of polygonosomy. Medical, psychological and social incidences of XXX, XXY, XYY, genotypes indicate that these chromosomal aberrations share identical features: phenotypic abnormalities (high stature, dermatoglyphes abnormalities), neuropsychic troubles (neurological symptoms and mental fragility) and antisocial tendancy. One can suppose that at least some polygonosomic persons have a minimal brain dysfunction (or damage), which causes more vulnerability to environnement, deprivation and stress. Relational, educational and socio-economical factors appear now to have a marked role in the etiopathogenesis of these psychiatric troubles. Some forensic and ethical problems of human genetic research are reviewed, such as the so-called "criminal chromosome", supplementary Y chromosome, a myth based upon false and premature scientific assertions.