Single case study. Behavioral treatment of boy with 47,XYY karyotype

Controversy exists with regard to the genetic programmability of antisocial, aggressive behavior in males with 47,XYY karyotype. This study reports the reduction of disruptive behavior in a 7-year-old boy with this chromosomal anomaly. Behavioral manipulations of environmental contingencies were used to alter several types of problematic behaviors successfully. Theoretical and clinical implications with regard to the notion of genetic causality are discussed.