Gender and sexual orientation differences in sexual response to sexual activities versus gender of actors in sexual films.

In this study, the authors investigated the hypothesis that women's sexual orientation and sexual responses in the laboratory correlate less highly than do men's because women respond primarily to the sexual activities performed by actors, whereas men respond primarily to the gender of the actors. The participants were 20 homosexual women, 27 heterosexual women, 17 homosexual men, and 27 heterosexual men. The videotaped stimuli included men and women engaging in same-sex intercourse, solitary masturbation, or nude exercise (no sexual activity); human male-female copulation; and animal (bonobo chimpanzee or Pan paniscus) copulation. Genital and subjective sexual arousal were continuously recorded. The genital responses of both sexes were weakest to nude exercise and strongest to intercourse. As predicted, however, actor gender was more important for men than for women, and the level of sexual activity was more important for women than for men. Consistent with this result, women responded genitally to bonobo copulation, whereas men did not. An unexpected result was that homosexual women responded more to nude female targets exercising and masturbating than to nude male targets, whereas heterosexual women responded about the same to both sexes at each activity level. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is homophobia associated with homosexual arousal?

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 to sexually explicit erotic stimuli consisting of heterosexual, male homosexual, and lesbian videotapes, and changes in penile circumference were monitored. They also completed an Aggression Questionnaire (A. H. Buss & M. Perry, 1992). Both groups exhibited increases in penile circumference to the heterosexual and female homosexual videos. Only the homophobic men showed an increase in penile erection to male homosexual stimuli. The groups did not differ in aggression. Homophobia is apparently associated with homosexual arousal that the homophobic individual is either unaware of or denies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Homosexual threat, negative attitudes toward masturbation, sex guilt, and males' sexual and affective reactions to explicit sexual films.

Subjective sexual arousal and affective responses of 215 undergraduate males to films of masturbatory, homosexual, and heterosexual behavior were studied as a function of personality differences in negative attitudes toward masturbation, homosexual threat, and sex guilt. The film of heterosexual behavior elicited more subjective sexual arousal and less disgust, anger, shame, depression, and guilt than did the films of male masturbation and homosexuality. The film of homosexuality elicited both more sexual arousal and more disgust, anger, shame, and guilt than did the film of masturbation. The personality inventories (e.g., Mosher Forced-Choice Guilt Inventory, Negative Attitudes Toward Masturbation Inventory) predicted sexual arousal and affective reactions, but the evidence was better for convergent than for discriminant validity. A promising new measure of homosexual threat (Homosexual Threat Inventory) was constructed that was predictive of heterosexual–homosexual orientation and reactions to the films. The concept of homosexual threat is differentiated from the concepts of fear of homosexuals, homosexual panic, and homosexual prejudice. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual orientation differences in cerebral asymmetry and in the performance of sexually dimorphic cognitive and motor tasks

With each of the tasks in the present studies we expected to find the reported sex difference between heterosexual women and heterosexual men and we predicted a sexual orientation effect with the performance of homosexual men being similar to that of heterosexual women and different from that of heterosexual men. Study 1 aimed to replicate earlier findings by recording the performance of a group of homosexual men on a visuospatial task, the Vincent Mechanical Diagrams Test (VMDT), a dot detection divided visual field measure of functional cerebral asymmetry, and on five subtests of the Wechsler Adult Intelligence Scale (WAIS). For each task the profile of scores obtained for the homosexual men was similar to that of heterosexual women in that they scored lower than heterosexual men on the VMDT, they showed less asymmetry, and they recorded a higher Verbal than Performance IQ on the WAIS. In Study 2, a male-biased targeted throwing task favored heterosexual men while, in contrast, on the female-biased Purdue Pegboard single peg condition heterosexual men were outperformed by heterosexual women and homosexual men. On neither of these two tasks did the performances of homosexual men and heterosexual women differ. One task, manual speed, yielded neither sex nor sexual orientation differences. Another, the Purdue Pegboard assemblies condition, revealed a sex difference but no sexual orientation difference. Failure to obtain a sexual orientation difference in the presence of a sex difference suggests that the sexual orientation effect may be restricted to a subset of sexually dimorphic tasks.     

Sexual orientation-related differences in prepulse inhibition of the human startle response.

Prepulse inhibition (PPI) refers to a reduction in the startle response to a strong sensory stimulus when this stimulus is preceded by a weaker stimulus--the prepulse. PPI reflects a nonlearned sensorimotor gating mechanism and also shows a robust gender difference, with women exhibiting lower PPI than men. The present study examined the eyeblink startle responses to acoustic stimuli of 59 healthy heterosexual and homosexual men and women. Homosexual women showed significantly masculinized PPI compared with heterosexual women, whereas no difference was observed in PPI between homosexual and heterosexual men. These data provide the first evidence for within-gender differences in basic sensorimotor gating mechanisms and implicate the known neural substrates of PPI in human sexual orientation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Specific Sexual Orientation-Related Difference in Navigation Strategy.

During spatial navigation, women typically navigate an environment using a landmark strategy, whereas men typically use an orientation strategy. To examine the as yet unknown effects of sexual orientation on these normative sex differences, this study required 80 healthy heterosexual and homosexual adult men and women to provide directions from experimental maps for 4 routes. The frequency and type of strategy used by each participant were computed. Expected sex differences were demonstrated, and a robust cross-sex shift was shown by homosexual men in using landmarks. This remained after controlling for differences in mental rotation, directional sense, and general intelligence. The findings may limit the number of putative neurodevelopmental pathways responsible for sex differences in navigation strategy utility. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual orientation and handedness in men and women: A meta-analysis.

Recent findings suggest that sexual orientation has an early neurodevelopmental basis. Handedness, a behavioral marker of early neurodevelopment, has been associated with sexual orientation in some studies but not in others. The authors conducted a meta-analysis of 20 studies that compared the rates of non-right-handedness in 6,987 homosexual (6,182 men and 805 women) and 16,423 heterosexual (14,808 men and 1,615 women) participants. Homosexual participants had 39% greater odds of being non-right-handed. The corresponding values for homosexual men (20 contrasts) and women (9 contrasts) were 34% and 91%, respectively. The results support the notion that sexual orientation in some men and women has an early neurodevelopmental basis, but the factors responsible for the handedness-sexual orientation association require elucidation. The authors discuss 3 possibilities: cerebral laterality and prenatal exposure to sex hormones, maternal immunological reactions to the fetus, and developmental instability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual orientation and the second to fourth finger length ratio: A meta-analysis in men and women.

The ratio of the lengths of the second and fourth fingers (2D:4D) may serve as a marker for prenatal androgen signaling. Because people are typically unaware of their 2D:4D, its use allows possible effects of early sex hormone regimes and socialization to be disentangled. We conducted a meta-analysis on relationships between 2D:4D and sexual orientation in men and women in 18 independent samples of men and 16 independent samples of women. Collectively, these samples comprised 1,618 heterosexual men, 1,693 heterosexual women, 1,503 gay men, and 1,014 lesbians. In addition to identifying the normative heterosexual sex difference in 2D:4D for both hands, we found that heterosexual women had higher (more feminine) left- and right-hand 2D:4D than did lesbians, but we found no difference between heterosexual and gay men. Moderator analyses suggested that ethnicity explained some between-studies variation in men. These results add to a literature suggesting that early sex hormone signaling affects sexual orientation in women, and highlight the need for further research exploring the relationships among 2D:4D, sexual orientation, and ethnicity in men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hair whorl direction and sexual orientation in human males.

Hair whorl direction is a somatic feature that is organized early during neurodevelopment and unlikely to be influenced by social factors. This study aimed to replicate a widely reported association by A. J. S. Klar (2003) between counterclockwise hair whorl direction and homosexuality in men, using more objective methodology. The authors took digital photographs of parietal surface hair whorls from 100 heterosexual men and 100 homosexual men who were predominantly right-handed. These images were rated for clockwise and counterclockwise direction (for which no more than 1 hair whorl was present) by 2 raters unaware of sexual orientation. The authors found no significant difference between heterosexual and homosexual men in hair whorl direction, but the authors did replicate the fraternal birth order effect (more older brothers for homosexual men). Number of older sisters was positively correlated with counterclockwise hair whorls in heterosexual men. These data were discussed in relation to prenatal factors assumed to play a role in the neurodevelopment of male homosexuality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Within-group differences in sexual orientation and identity.

The purpose of this investigation was to examine within-group differences among self-identified sexual orientation and identity groups. To understand these within-group differences, 2 types of analysis were conducted. First, a sample of 2,732 participants completed the Sexual Orientation and Identity Scale. Cluster analyses were used to identify 3 types of bisexual women, 3 types of bisexual men, 2 types of heterosexual women, and 2 types of gay men. Lesbians and heterosexual men were clustered into singular groupings. In addition, a subsample of 838 participants also completed measures of sexual identity development and lesbian, gay, and bisexual knowledge and attitudes. Within-group differences were found for bisexual men and women, gay men, and heterosexual women along these dimensions. Findings supported the existence of distinct subgroups of bisexual men, bisexual women, gay men, and heterosexual women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A follow-up study of girls with gender identity disorder.

This study provided information on the natural histories of 25 girls with gender identity disorder (GID). Standardized assessment data in childhood (mean age, 8.88 years; range, 3-12 years) and at follow-up (mean age, 23.24 years; range, 15-36 years) were used to evaluate gender identity and sexual orientation. At the assessment in childhood, 60% of the girls met the Diagnostic and Statistical Manual of Mental Disorders criteria for GID, and 40% were subthreshold for the diagnosis. At follow-up, 3 participants (12%) were judged to have GID or gender dysphoria. Regarding sexual orientation, 8 participants (32%) were classified as bisexual/homosexual in fantasy, and 6 (24%) were classified as bisexual/homosexual in behavior. The remaining participants were classified as either heterosexual or asexual. The rates of GID persistence and bisexual/homosexual sexual orientation were substantially higher than base rates in the general female population derived from epidemiological or survey studies. There was some evidence of a "dosage" effect, with girls who were more cross-sex typed in their childhood behavior more likely to be gender dysphoric at follow-up and more likely to have been classified as bisexual/homosexual in behavior (but not in fantasy). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interaction of fraternal birth order and body size in male sexual orientation.

A late fraternal birth order has been demonstrated numerous times in homosexual men. Body size has been less studied with regard to the development of sexual orientation and has demonstrated contradictory results. In this research, the relations among fraternal birth order, body size, and sexual orientation were examined in a Canadian sample of homosexual and heterosexual men. An interaction between fraternal birth order and height was observed, with a homosexual orientation most likely to occur in men with a high number of older brothers and shorter stature. No significant interactive effects were observed for weight. The results suggest that the mechanism underlying the fraternal birth order phenomenon has an effect on physical development that lasts and is detectable into adulthood (i.e., adult stature). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of sexual orientation and masculinity on young men's tobacco smoking.

Objective: The prevalence of smoking among gay men is considerably higher than in the general population. To investigate possible causes of this health risk disparity, this study used multilevel modeling of daily diary data to examine the temporal relationship between smoking and both sexual orientation concealment and masculine gender role variables. Method: Gay (n = 136) and heterosexual (n = 56) university students (mean age = 20.56, SD = 2.13) completed measures of boyhood and current gender nonconformity, as well as daily measures of smoking, negative affect, and masculinity self-consciousness across 9 days. Gay participants additionally indicated the extent to which they concealed their sexual orientation each day. Results: The same percentage of gay (17.7%; n = 24) and heterosexual (17.9% n = 10) participants smoked over the course of the study. Gay men who smoked, however, smoked on more days across the study, t = 2.20, p     

Swagger, sway, and sexuality: Judging sexual orientation from body motion and morphology.

People can accurately judge the sexual orientation of others, but the cues they use have remained elusive. In 3 studies, the authors examined how body shape and motion affect perceived sexual orientation. In 2 studies, participants judged the sexual orientation of computer-generated animations in which body shape and motion were manipulated. Gender-typical combinations (e.g., tubular body moving with shoulder swagger or hourglass body moving with hip sway) were perceived generally to be heterosexual; gender-atypical combinations were perceived generally to be homosexual. These effects were stronger for male targets. Body shape affected perceived sexual orientation of women, but motion affected perceived sexual orientation of both men and women. Study 3 replicated and extended these findings. Participants judged dynamic outlines of real people (men and women, both gay and straight) in which body shape and motion were measured. Again, gender-atypical body motion affected perceived sexual orientation and, importantly, affected accuracy as well. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contingent negative variation (CNV) and erotic preference in self-declared homosexuals and in child sex offenders

Contingent negative variation (CNV) was recorded bilaterally from central electrodes using a "match/mismatch" paradigm in (Study 1) samples of heterosexual men (N = 6), gay men (N = 10) and lesbian women (N = 14) and (Study 2) in samples of child sex offenders (N = 34) and heterosexual control men (N = 19). Sexual orientation was assessed using the Multidimensional Scale of Sexuality (MSS) and the Human Sexuality Questionnaire (HSQ). Separate CNV averages were formed for each condition of stimulation: for Study 1, slides of adult male and female nudes; for Study 2, slides of child, pubescent and adult male and female nudes. Penile plethysmographic (PPG) data were also obtained from 15 of the child sex offender sample while they viewed stimuli of the same categories as were used in the CNV recording. On the basis of their PPG responses to children, child sex offenders were classified as either "pedophiles" or "non-pedophiles". In Study 1 significant Group x Sex (of slide) and Group x Electrode interactions indicated that: (i) heterosexual men (but neither homosexual group) showed significantly larger CNVs to female than to male slides; (ii) both homosexual groups showed significantly asymmetrical (R > L) CNVs. In Study 2, controls showed significantly greater CNVs to adult females than to both adult males and female children. Child sex offenders showed no significant differences in CNV to male and female slides for any age. "Non-pedophiles" showed significantly larger CNVs to female adults than to female children, but "pedophiles" did not. It is concluded that CNV has promise as a measure of both deviant and non-deviant sexual preference.     

HIV surveillance among sexually transmitted disease clinic attenders in Amsterdam, 1991-1996

OBJECTIVE: To determine trends in HIV prevalence among attenders of a clinic for sexually transmitted diseases (STD), with emphasis on heterosexuals who did not have a history of injecting drug use. METHODS: Anonymous unlinked HIV surveys with individual consent, conducted each half year from 1991 to 1996 (except 1993) among STD clinic attenders who came for evaluation of a possible new STD episode. RESULTS: Of 10,940 eligible attenders 10,046 (92%) accepted HIV testing. Of all tested attenders, 312 (3.1%) were HIV-infected. Overall HIV prevalence decreased significantly from 4.6% in 1991 to 2.8% in 1996. HIV prevalence among heterosexual men and women who were not injecting drug users was less than 1% in all but one survey period. Except for one woman, none of the 48 HIV-infected heterosexuals was aware of their current serostatus. Among HIV-infected heterosexuals, 21 out of 28 males (75%) and 18 out of 20 females (90%) were of non-Dutch origin. HIV prevalence was 16% among all homosexual men, and 12% among young homosexual men aged < 30 years. HIV prevalence among young homosexual men decreased significantly over time. Among HIV-infected homosexual men, 58% of older men and 59% of younger men were not aware of their current HIV infection. Rates of current STD were generally significantly higher among HIV-infected participants compared with non-HIV-infected participants. CONCLUSIONS: Although HIV prevalence among heterosexual clinic attenders is low, there is a clear potential for ongoing sexual HIV transmission. Most heterosexually acquired HIV infections are found in non-Dutch persons. This observation suggests migration of HIV-infected heterosexuals or the separation of Dutch and non-Dutch heterosexual networks. Awareness of serostatus is almost non-existent among HIV-infected heterosexuals, and is low among male homosexual clinic attenders. To increase awareness of current HIV serostatus and possibly decrease risk behaviour, HIV counselling and testing should be offered actively to all clinic attenders.     

Large sexual-orientation-related differences in performance on mental rotation and judgement of line orientation tasks.

This study examined the performance of heterosexual and homosexual men and women on 2 tests of spatial processing, mental rotation (MR) and Benton Judgment of Line Orientation (JLO). The sample comprised 60 heterosexual men, 60 heterosexual women, 60 homosexual men, and 60 homosexual women. There were significant main effects of gender (men achieving higher scores overall) and Gender×Sexual Orientation interactions. Decomposing these interactions revealed large differences between the male groups in favor of heterosexual men on JLO and MR performance. There was a modest difference between the female groups on MR total correct scores in favor of homosexual women but no differences in MR percentage correct. The evidence suggests possible variations in the parietal cortex between homosexual and heterosexual persons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual compulsivity, state affect, and sexual risk behavior in a daily diary study of gay and bisexual men.

Researchers have identified a strong link between sexual compulsivity (SC) and risky sexual behavior among men who have sex with men (MSM). Meanwhile, affect/mood has also been connected with negative sexual health outcomes (sexually transmitted infection/human immunodeficiency virus [HIV] transmission, sexual risk, sex under the influence of drugs/alcohol). Given that SC is characterized by marked distress around one's own sexual behavior, affect may play a central role in SC and HIV risk behavior. Data were taken from the Pillow Talk Project, a pilot study conducted in 2008–2009 with 50 highly sexually active MSM (9 or more male sex partners, ≤ 90 days), of which half displayed SC symptoms and half did not. Forty-seven men completed a daily diary online for 30 days (n = 1,060 diary days), reporting on their sexual behavior and concurrent affect: positive activation, negative activation, anxious arousal, and sexual activation. We conducted HLM analyses using daily affect (Level 1, within subjects) and SC and HIV status (Level 2, between subjects) to predict sexual behavior outcomes. Increased negative activation (characterized by fear, sadness, anger, and disgust) was associated with reduced sexual risk behavior, but less so among sexually compulsive MSM. Sexual activation was associated with increased sexual risk taking, but less so among sexually compulsive MSM. Anxious arousal was associated with increased sexual behavior, but not necessarily sexual risk taking. Findings indicate that affect plays key roles in sexual behavior and sexual risk taking; however, the association between affect and behavior may be different for sexually compulsive and non-sexually compulsive MSM. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual histories, partnerships and networks associated with the transmission of gonorrhoea

We aimed to describe and compare sexual links among people with gonorrhoea, by studying patients in 2 UK departments of genitourinary medicine. Interviews were completed for 510 and 235 cases in London and Sheffield respectively. There was a greater proportion of cases in men, homosexual men, non-white and non-British people and fewer female sex workers in London. Total networks of 1738 people in London and 570 people in Sheffield were described. Large linked heterosexual networks identified in Sheffield were associated with local contact, including men with higher numbers of sexual partners. Condom use for vaginal sex was reported for 11% of heterosexual partnerships in Sheffield, and 27% in London, with little difference between regular and casual partners. It was more difficult to define networks in London due to a high proportion of relatively anonymous contacts. These difficulties suggest that research and interventions may profitably focus upon venues for meeting partners as well as partner notification.     

Pain sensitivity and individual differences in self-reported sexual behavior.

The relationship between sexual behavior and pain sensitivity was assessed in 27 heterosexual men and 20 heterosexual women. Sexual behavior measures included sexual motivation and ratings of subjective sexual arousal to and enjoyment of an auditory stimulus. Pain sensitivity measures were pain threshold and pain tolerance in a cold pressor task. Participants were tested after exposure to a neutral or a sexual audio stimulus. Exposure to the sexual stimulus increased pain sensitivity in women but not in men. However, sexual behavior measures were correlated with pain threshold for both men and women. Specifically, higher pain thresholds were associated with weaker sexual motivation, lower enjoyment potential for sexual interaction, and increased inhibition during intercourse. These results are consistent with findings in laboratory animals, suggesting that differences in sexual behavior may reflect differences in responsiveness to a variety of stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)