The XYY karyotype and criminality: A review

Abstract

CRIMINALITY was once thought to be the result of demonic or supernatural forces. Beginning with the eighteenth century, attempts were made to attribute criminal behavior to certain physical characteristics of the individual. Gall and Spurzheim, for example, attempted to associate various bumps on the head with specific personality traits. In Italy, Cesare Lombroso, and in the United States Ernest Hooton, argued that criminal behavior reflected an ativistic level of biological organization which had its concomitants in certain physical stigmata or anthropometric ‘marks of inferiority’.1 More recently, SHELDON,~ S. and E. GLUECK,~ and others4 have reported a relationship between criminality and bodily physique. The contribution of genetic factors to the production of criminal behavior is expressed in the concept of ‘bad seed’ and is explicit in the studies of SIR FRANCIS GALTON~ and of the Jukes and Kallikak families by DUGDALE~ and GODDARD’ respectively. Attempts at estimating the hereditary contribution to criminal behavior have been made by means of twin studies.8 But, the confounding of common genotypic and experiential factors among twin pairs make these studies difficult to interpret. In recent years fresh interest in possible genotypic contributions to criminal behavior has arisen due to the finding of a relatively large number of individuals with various chromosomal abnormalities in maximum security institutions for the mentally ill, the mentally subnormal, and among prison populations. Several recent crimes of violence perpetrated by individuals who subsequently were shown to have an abnormal chromosomal constitution have also received wide notoriety. Two specific cases stand out. In. both, the grounds for the defense rested heavily on arguments of legal irresponsibility resulting from the fact that the defendant carried a 47,XYY* karyotype. In France, Daniel Hugon was convicted of murdering a prostitute. During the course of his trial a special commission was appointed by the court to testify on the possible contribution of the chromosomal abnormality to the crime. The jury, apparently allowing for extenuating circumstances, decided on a somewhat lesser penalty than usual for this type of crime. In Australia, Lawrence E. Hammell was acquitted of murder on the grounds that he was legally insane at the time of the crime. According to newspaper accounts,10 the * The nomenclature is that established at the Chicago Conference, 1966.9 In further citations, we will refer to this karyotype only as XYY.