PRENATAL TESTOSTERONE LEVELS IN XXY AND XYY MALES

It has been postulated that behavioural differences between normal mal es and those with an additional X or Y chromosome may be related to pr e- or postnatal hormonal variations. The prenatal hormone status was i nvestigated using amniotic fluid obtained at antenatal diagnosis betwe en 16 and 20 weeks gestation from fetuses with sex chromosome abnormal ities and from controls of the same gestational age. After log transfo rmation, the (geometric) mean testosterone levels were XY 439.4 pmol/l , range 165-1,027 (n = 29), XYY 490.7 pmol/l, range 224-1,092 (n = 20) ; and XXY 419 pmol/l, range 87-1,021 (n = 20). There were no significa nt differences between the three male groups and all three were signif icantly higher than the XX fetuses at 147.0 pmol/l, range 41-474 (p < 0.001). These findings give no support to the hypothesis that prenatal testosterone levels contribute to later behavioural characteristics.