XYY syndrome: a condition identified by a
supernumerary Y-chromosomal anomaly in
morphologic males who are typically over 6 feet (183 cm) in height, and are likely to have one or more of a varied assortment of congenital physical anomalies, including sterility in some cases. The basic genetic defect is an extra
sex chromosome with a total count of 47,XYY, although other variants also occur, e.g. 48XXYY; 48,XYYY. In behavioral development, there is an increased risk of
impulsiveness, including
antisocial and
lawbreaking impulsiveness.
Dictionary of Sexology Project: Main Index