ABSTRACT
XYY chromosomes A chromosome is a rod-shaped structure in the nucleus of each cell in the human body. There are twenty-three pairs of chromosomes in the human body, of which in females one pair is XX and in males one pair is XY. Of various known chromosomal abnormalities that of an extra Y male chromosome in males first began to attract attention in the 1960s. Price and Whatmore (1967a, b) drew a profile of characteristics of XYY males drawn from a Scottish special hospital, linking their criminal activity with the presence of an extra Y chromosome. Reviews of the studies done to date (Hoffman, 1977; Owen, 1972) give a less certain picture than some of the early claims that the basis for aggressive psychopathy had been discovered, emphasising the role of subjective judgments in identification, an equal prevalence of XYY males in the normal population and the lack of a strikingly different clinical profile for these men from controls. Even when the issues are wholly clarified, at best chromosomal abnormality can have a bearing on only a minute fraction of the criminal population.
