Genome-wide scan demonstrates significant linkage for male sexual orientation - Volume 45 Issue 7 - A. R. Sanders, E. R. Martin, G. W. Beecham, S. Guo, K. Dawood, G. Rieger, J. A. Badner, E. S. Gershon, R. S. Krishnappa, A. B. Kolundzija, J. Duan, P. V. Gejman, J. M. Bailey

Whether animals ever exhibit a preference for same-sex sexual partners is a subject of debate. Japanese macaques represent excellent models for examining issues related to sexual preference in animals because females, in certain populations, routinely engage in both heterosexual and homosexual behavior over the course of their life spans. Multiple lines of evidence indicate that female homosexual behavior in Japanese macaques is a sexual behavior, not a sociosexual one. Additional evidence indicates that female Japanese macaques do not engage in homosexual behavior simply because acceptable male mates are unavailable or unmotivated to copulate. Patterns of sexual partner choice by female Japanese macaques that are the focus of intersexual competition indicate that females of this species choose same-sex sexual partners even when they are simultaneously presented with a motivated, opposite-sex alternative. Thus, in some populations of Japanese macaques, females prefer certain same-sex sexual partners relative…