Genetic and Environmental Effects on Sexual Excitation and Sexual Inhibition in Men

Abstract

The Sexual Inhibition and Sexual Excitation Scales (SIS/SES) measure the propensity for sexual inhibition and excitation in men. According to the theoretical model underlying the SIS/SES, sexual response and associated behavior depend on dual control mechanisms in the brain involving the balance of excitatory and inhibitory systems which impinge on sexual response. Previous research with the SIS/SES has indicated one higher-order excitatory factor and two higher-order inhibitory factors affecting sexual response. The present study analyzed the item structure and the psychometric properties of the instrument in a population based sample of Finnish male twins (N = 1,289), and, including 37 out of 45 items of the original scales, estimated the heritability of and the environmental influences on the excitatory and inhibitory mechanisms.

The twin correlations and the structural equation modeling suggested modest heritability for both inhibitory mechanisms. Sexual excitation, in contrast, was not influenced by genetic effects and similarities between twins for this mechanism seemed to be caused by the common environment of the twins.

This research was financed by Grant No. 210298 from the Academy of Finland and a Centre of Excellence Grant from the Stiftelsen för Åbo Akademi–Foundation. We would like to thank Frühling Rijsdijk and Nicole Harlaar for statistical advice and helpful comments on a draft of the paper, as well as the anonymous reviewers for their insightful opinions. Correspondence concerning this article should be adressed to Markus Varjonen, Åbo Akademi, Department of Psychology, 20500 Turku, Finland. E-mail: [email protected]

Notes

∗When loading on several factors, an item was included in the factor on which its loadings were strongest.