ABSTRACT
In the 1970s H. A. Witkin and collaborators initiated a case-finding study in Denmark on men with sex chromosome anomalies in the general population unselected with regard to institutionalization. Two types of controls were assigned, designated “No Borge-Prien Prove (BPP)” and “BPP,” respectively. The “No BPP” control was matched individually to the sex anomaly case for age, height, and social class. As S. Kessler and R. H. Moss point out, ascribing specific behavioural effects to a single chromosome fails to take into account a broad range of relevant environmental factors, and also ignores the fact that phenotypes result from the total integrative properties of genome-environment interactions. The most distinct differences appearing between the two groups are related to the sexual domain. The XYYs are younger at first intercourse, have a higher frequency of masturbation both in childhood and adulthood, report more libido and unconventional sex, and have more partners than the XXYs.
