Xyy Syndrome

Based in Lombrosian theory that criminal behavior is rooted in heredity, some contemporary theorists have focused their research on genetic composition that may influence or even cause criminal conduct. The notion that criminal conduct may be biologically predisposed is certainly not new, nor is it without foundation. However, the research on genetic makeup, specifically the XYY chromosomal syndrome, has been very controversial. In 1965, Jacobs and associates reported that the presence of an extra Y chromosome in human males was correlated with mental retardation, tall stature, and excessive levels of aggressive conduct. This report spawned a number of researchers to hypothesize that the XYY chromosomal anomaly was related to violent crime by certain males.

Chromosomes are chains of genetic material known as DNA, which direct the ...