Studies have used manipulated faces to test the preferences of heterosexual individuals for sexually dimorphic facial cues. In contrast to previous studies, which have generally excluded homosexual participants, we directly compared homosexual and heterosexual male and female preferences for manipulated sexual dimorphism in faces (homosexual males: n = 311; heterosexual males: n = 215; homosexu...

Is sexual orientation associated with structural differences in the brain? To address this question, 80 homosexual and heterosexual men and women (16 homosexual men and 15 homosexual women) underwent structural MRI. We used voxel-based morphometry to test for differences in grey matter concentration associated with gender and sexual orientation. Compared with heterosexual women, homosexual wome...

San Francisco (SF) has been chosen as the site for modeling HIV transmission in homosexual men because very good data are available there . The large open community of homosexual men in SF has been the source of numerous sexual behavior surveys . Additionally, data are available in SF for AIDS incidence each year and for HIV incidence as early as 1978 . In this application of the simulation mod...

Diverse animal groups exhibit homosexual interactions, yet the evolutionary maintenance of such behaviours remains enigmatic as they do not directly increase reproductive success by generating progeny. Here, we use Tribolium castaneum flour beetles, which exhibit frequent male homosexual copulations, to empirically test several hypotheses for the maintenance of such behaviours: (1) establishing...

In research with 942 nonclinical adult participants, gay men and lesbian women reported a significantly higher rate of childhood molestation than did heterosexual men and women. Forty-six percent of the homosexual men in contrast to 7% of the heterosexual men reported homosexual molestation. Twenty-two percent of lesbian women in contrast to 1% of heterosexual women reported homosexual molestat...

The authors investigated the role of homosexual arousal in exclusively heterosexual men who admitted negative affect toward homosexual individuals. Participants consisted of a group of homophobic men (n = 35) and a group of nonhomophobic men (n = 29); they were assigned to groups on the basis of their scores on the Index of Homophobia (W. W. Hudson & W. A. Ricketts, 1980). The men were exposed ...

Previous studies have shown that homosexual men differ from heterosexual men in several somatic traits and lay people accurately attribute sexual orientation based on facial images. Thus, we may predict that morphological differences between faces of homosexual and heterosexual individuals can cue to sexual orientation. The main aim of this study was to test for possible differences in facial s...

In adult male samples, homosexuality is associated with a preponderance of older brothers (i.e., the fraternal birth order effect). In several studies comparing gender dysphoric youth, who are likely to be homosexual in adulthood, to clinical or non-clinical control groups, the findings have been consistent with the fraternal birth order effect in males; however, less is known about unique sibs...

The purpose of this study was to determine if self-identified bisexual, heterosexual, and homosexual men show differential genital and subjective arousal patterns to video presentations of bisexual, heterosexual, male homosexual, and lesbian sexual interactions. It was predicted that, relative to heterosexual and homosexual stimuli, bisexual men would show the highest levels of sexual arousal t...