Digit Ratio (2D:4D) in Homosexual and Heterosexual Men from Austria

Neurohormonal theories of sexual orientation emphasize the organizational effects of testosterone on the developing brain. A recent suggestion, that the ratio of the length of the 2nd and 4th digits (2D:4D) is negatively correlated with prenatal testosterone, has led to a number of studies of 2D:4D in homosexual and heterosexual men and women. The results have been mixed. In comparison to heterosexual men, mean 2D:4D in gay men has been reported to be hypermasculinized (lower 2D:4D), hypomasculinized (higher 2D:4D), or to show no significant difference. Here, we report mean 2D:4D in Austrian homosexual and heterosexual men. We found no significant difference between means for homosexual and heterosexual 2D:4D, with values for both falling between 0.96 to 0.97. There are now 6 reports of 2D:4D in heterosexual and homosexual men. Considering Caucasian men, the studies from the United States show low heterosexual mean 2D:4D, and homosexual mean 2D:4D is higher or similar to that of heterosexuals. The European studies show high heterosexual mean 2D:4D, and comparisons with homosexuals reveal the latter to have lower or similar mean 2D:4D to that of heterosexuals. We discuss these results in relation to the suggestion that mean 2D:4D in heterosexual men differs across populations but mean 2D:4D in homosexuals shows less geographical variation (the “uniform mean hypothesis”). It is concluded that more data are required to clarify whether or not there is a 2D:4D effect for sexual orientation in men.This revised article was published online in June 2005 with the book reviews as separate articles     

Handedness,sexual orientation,and gender-related personality traits in men and women

This study assessed large numbers of heterosexual and homosexual men and women on handedness and gender-related personality traits. Initial analyses employed a dichotomous measure of handedness (right-handed vs. non–right-handed). For men and women combined, homosexual participants had 50% greater odds of being non–right-handed than heterosexual participants, a statistically significant difference. Homosexual men had 82% greater odds of being non–right-handed than heterosexual men, a statistically significant difference, whereas homosexual women had 22% greater odds of being non–right-handed than heterosexual women, a nonsignificant difference. When participants were classified into five graduated categories of handedness, both men and women showed significant homosexual–heterosexual differences in handedness distributions. Within groups, handedness showed a number of weak but statistically significant associations with sex-typed occupational preferences, self-ascribed masculinity, and self-ascribed femininity, but not with instrumentality or expressiveness. Rates of non–right-handedness were virtually identical for heterosexual men and women, suggesting that sex differences in handedness may result from higher rates of homosexuality in men.     

Homosexual Mating Preferences from an Evolutionary Perspective: Sexual Selection Theory Revisited

Studies in evolutionary psychology and sexual selection theory show that heterosexual men prefer younger mating partners than heterosexual women in order to ensure reproductive success. However, previous research has generally not examined differences in mating preferences as a function of sexual orientation or the type of relationship sought in naturalistic settings. Given that homosexual men seek partners for reasons other than procreation, they may exhibit different mating preferences than their heterosexual counterparts. Moreover, mating preferences may show important differences depending on whether an individual is seeking a long-term versus a short-term relationship. The purpose of the present study was to examine these issues by comparing partner preferences in terms of age and relationship type between homosexual and heterosexual men placing internet personal advertisements. Participants included 439 homosexual and 365 heterosexual men who placed internet ads in the U.S. or Canada. Ads were coded for the participant’s age, relationship type (longer-term or short-term sexual encounter) sought, and partner age preferences. Significantly more homosexual than heterosexual men sought sexual encounters, although men (regardless of sexual orientation) seeking sexual encounters preferred a significantly wider age range of partners than men seeking longer-term relationships. These findings suggest that partner preferences are independent of evolutionary drives to procreate, since both types of men preferred similar ages in their partners. In addition, they highlight the importance of examining relationship type in evolutionary studies of mating preferences, as men’s partner preferences show important differences depending upon the type of relationship sought.     

Body Image Satisfaction in Heterosexual,Gay, and Lesbian Adults

Does the prevalence and degree of body dissatisfaction differ among heterosexual and homosexual men and women? Some theorists have suggested that, compared to their heterosexual peers, gay men are at greater risk for body dissatisfaction and lesbians at lower risk. Past studies examining this issue have generally relied on small samples recruited from gay or lesbian groups. Further, these studies have sometimes produced conflicting results, particularly for comparisons of lesbian and heterosexual women. In the present research, we compared body satisfaction and comfort with one’s body during sexual activity among lesbian women, gay men, heterosexual women, and heterosexual men through two large online studies (Ns = 2,512 and 54,865). Compared to all other groups, heterosexual men reported more positive evaluations of their appearance, less preoccupation with their weight, more positive effects of their body image on their quality of life and the quality of their sex life, more comfort wearing a swimsuit in public, and greater willingness to reveal aspects of their body to their partner during sexual activity. Few significant differences were found among gay men, lesbian women, and heterosexual women. Many gay men (42%) reported that their feelings about their body had negative effects on the quality of their sex life, as did some lesbian women (27%), heterosexual women (30%), and heterosexual men (22%). Overall, the findings supported the hypothesis that gay men are at greater risk than heterosexual men for experiencing body dissatisfaction. There was little evidence that lesbian women experience greater body satisfaction than heterosexual women.     

Same-sex sexuality and quality of life: findings from the Netherlands Mental Health Survey and Incidence Study

This study assessed differences in quality of life (QL) between homosexual and heterosexual people and attempted to identify factors accounting for observed differences. Data were collected in a representative sample of the Dutch population aged 18–64 (N = 7,076). Classification as heterosexual or homosexual was based upon reported sexual behavior in the preceding year; 84.8% of the total sample (N = 5,998) could be classified: 2.8% of 2,878 sexually active men and 1.4% of 3,120 sexually active women had had same-sex partners. Differences in QL were tested by analysis of variance. Factors accounting for observed differences in QL were identified by selecting determinants of QL on which homosexual and heterosexual people differed and including them with same-sex sexuality in multiple regression analyses. Homosexual men, but not women, differed from their heterosexual counterparts on various dimensions of QL. Lesser QL in homosexual men was predominantly explained by self-esteem and mastery. Same-sex sexuality contributed independently to some of the observed differences. Although same-sex sexuality is related to QL in men, the lack of association in women suggests that the link is mediated by other factors, indicating the need to explore in what respect the situation of homosexual men and women differs. This study also suggests the importance of finding out how lower sense of self-esteem and of mastery come about in homosexual men.     

Correlates of sexual orientation in the German Democratic Republic

From 5469 participants of a sexual inquiry in the German Democratic Republic, 90 homosexual and 107 heterosexual women and men were selected, aged 16–30. A comparison was made concerning aspects of leisure time and sexual life. Some differences appear with regard to leisure time between homosexual and heterosexual women and men. The importance of love and sexuality is as great for young homosexuals as it is for young heterosexuals, but the mode and quantity of their specific sexual activities differ. Homosexual women appear to be more sexually active than heterosexual women on some study parameters.     

Sex-Specificity in the Reward Value of Facial Attractiveness

Studies of the sex-specificity of sexual arousal in adults (i.e., the tendency to respond more strongly to preferred-sex individuals than non-preferred sex individuals) have suggested that heterosexual men, homosexual men, and homosexual women show stronger sex-specific responses than do heterosexual women. Evidence for a similar pattern of results in studies investigating the reward value of faces is equivocal. Consequently, we investigated the effects of (1) sexual orientation (homosexual vs. heterosexual), (2) sex (male vs. female), (3) image sex (preferred-sex vs. non-preferred-sex), and (4) the physical attractiveness of the individual shown in the image on the reward value of faces. Participants were 130 heterosexual men, 130 homosexual men, 130 heterosexual women, and 130 homosexual women. The reward value of faces was assessed using a standard key-press task. Multilevel modeling of responses indicated that images of preferred-sex individuals were more rewarding than images of non-preferred-sex individuals and that this preferred-sex bias was particularly pronounced when more physically attractive faces were presented. These effects were not qualified by interactions involving either the sexual orientation or the sex of our participants, however, suggesting that the preferred-sex bias in the reward value of faces is similar in heterosexual men, homosexual men, heterosexual women, and homosexual women.     

Detection of Sexual Orientation (“Gaydar”) by Homosexual and Heterosexual Women

Although there has been considerable research investigating the ability to identify sexual orientation from static images, or “gaydar,” few studies have considered the role of female sexual orientation or sexual interest (for example, sociosexual orientation) in judgment accuracy. In two studies, we investigated the sexuality detection ability, and masculinity and femininity as cues used in judgment. In Study 1, we recruited heterosexual (N = 55) and homosexual (N = 71) women to rate the sexual orientation of homosexual and heterosexual male and female targets (N = 80: 20 heterosexual men, 20 homosexual men, 20 heterosexual women, and 20 homosexual women). We found that detection accuracy was better than chance levels for both male and female targets and that male targets were more likely to be falsely labeled as homosexual than female targets were. Overall, female faces were more accurately identified as heterosexual or homosexual than male faces and homosexual female raters were biased towards labeling targets as homosexual. Sociosexuality did not influence the accuracy with which targets were identified as heterosexual or homosexual. In Study 2, 100 heterosexual and 20 homosexual women rated the stimulus for masculinity and femininity. Heterosexual women were rated as more feminine and less masculine than homosexual women and homosexual men were rated as more feminine and less masculine than heterosexual men. Sexual orientation of the judges did not affect the ratings. The results were discussed with a reference to evolutionary and cultural influences affecting sexual orientation judgment accuracy.     

Sexual Partner Age Preferences of Homosexual and Heterosexual Men and Women

The sexual age preferences of 192 adults (equal groups of heterosexual men, heterosexual women, homosexual men, and homosexual women) were examined. Participants rated the sexual attractiveness of pictures of 15 male and 15 female faces arranged into five apparent average age categories ranging from 18 to 60 years. It was predicted that homosexual and heterosexual men would prefer younger partners of their preferred sex than would homosexual and heterosexual women and that age preference would not vary with participant age. Both predictions were supported, although homosexual women preferred older partners than expected. Results suggest that age and sex preferences develop independently.     

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 I 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.     

Sex and Sexual Orientation Differences in Personality in China

Using data from an Internet survey, we assessed masculinity-femininity (self-ascribed masculinity-femininity [Self-MF], gender-related interests, instrumentality, expressiveness) and Big Five personality traits in a Chinese sample of 201 heterosexual men, 220 homosexual men, 353 heterosexual women, and 215 homosexual women. Sex differences and sexual orientation differences were largest for gender-related interests and Self-MF. Homosexual-heterosexual differences in emotional stability were opposite for men and women, supporting the “gender shift” over the “social stress” hypothesis. Sex and sexual orientation differences in gender-related interests, Self-MF, and emotional stability observed in China were consistent with those found in other countries, suggesting possible biological influences. In contrast, group differences in other traits were more variable, suggesting possible cultural influences.     

Suicidality and Sexual Orientation: Differences Between Men and Women in a General Population-Based Sample From The Netherlands

Homosexuality has been shown to be associated with suicidality and mental disorders. It is unclear whether homosexuality is related to suicidality, independently of mental disorders. This study assessed differences in lifetime symptoms of suicidality (death ideation, death wishes, suicide contemplation, and deliberate self-harm) between homosexual and heterosexual men and women, controlling for lifetime psychiatric morbidity. Interaction effects of age and the role of perceived discrimination were also examined. Data were collected on a representative sample of the Dutch population aged 18–64 years. Classification as heterosexual or homosexual was based upon reported sexual behavior in the preceding year. Of those sexually active, 2.8% of 2,878 men and 1.4% of 3,120 women had had same-sex partners. Homosexual men differed from their heterosexual counterparts on all four suicide symptoms (OR ranging from 2.58 to 10.23, with higher ORs for more severe symptoms), and on the sum total of the four symptoms; homosexual women only differed from heterosexual women on suicide contemplation (OR=2.12). Controlling for psychiatric morbidity decreased the ORs, but among men all associations were still significant; the significance for suicide contemplation among women disappeared. Younger homosexuals were not at lower risk for suicidality than older homosexuals in comparison with their heterosexual counterparts. Among homosexual men, perceived discrimination was associated with suicidality. This study suggests that even in a country with a comparatively tolerant climate regarding homosexuality, homosexual men were at much higher risk for suicidality than heterosexual men. This relationship could not only be attributed to their higher psychiatric morbidity. In women, there was no such clear relationship.     

The Relationship Between Digit Ratio (2D:4D) and Sexual Orientation in Men from China

We examined the relationship between 2D:4D digit ratio and sexual orientation in men from China and analyzed the influences of the components used to assess sexual orientation and the criteria used to classify individuals as homosexual on this relationship. A total of 309 male and 110 female participants took part in a web-based survey. Our results showed that heterosexual men had a significantly lower 2D:4D than heterosexual women and exclusively homosexual men had a significantly higher left 2D:4D than heterosexual men whereas only exclusively homosexual men had a significantly higher right 2D:4D than heterosexual men when sexual orientation was assessed via sexual attraction. The left 2D:4D showed a significant positive correlation with sexual identity, sexual attraction, and sexual behavior, and the right 2D:4D showed a significant positive correlation with sexual attraction. The effect sizes for differences in 2D:4D between homosexual and heterosexual men varied according to criteria used to classify individuals as homosexual and sexual orientation components; the more stringent the criteria (scores closer to the homosexual category), the larger the effect sizes; further, sexual attraction yielded the largest effect size. There were no significant effects of age and latitude on Chinese 2D:4D. This study contributes to the current understanding of the relationship between 2D:4D and male sexual orientation.     

Coping Styles as Mediator of Sexual Orientation-Related Health Differences

The higher prevalence of health problems in homosexual compared to heterosexual populations is usually understood as a consequence of minority stress. We hypothesized that differential rates of health problems also could result from sexual orientation-related differences in coping styles. We explored this using data collected in a general population-based study (N = 9684) via face-to-face interviews. A higher prevalence of both mental and physical health problems, as assessed with individual questions, the GHQ-12, and checklists, was observed in homosexual compared to heterosexual men and women. Coping style was related to sexual orientation in men, but not in women. Compared to heterosexual men, homosexual men more strongly applied emotion-oriented and avoidance coping strategies. Emotion-oriented coping mediated the differences in mental and physical health between heterosexual and homosexual men. Findings suggest the importance of further exploration of the development and use of emotion-oriented and avoidance coping by homosexual men.     

The Subtlety of Sex-Atypicality

Memories of sex-atypical behavior and interests in childhood usually differ between homosexual and heterosexual people. However, variation within these broad groups has not previously been explored in detail, especially among women. We utilized data from a postal survey of a nationwide sample of Australian adult twins (n = 4,901, age range: 19–52 years). Among men, 15.2% reported homosexual behavior (ever), 11.5% said they had been sexually attracted to the same sex, and 6.4% said they were not heterosexual; the corresponding figures for women were 7.9, 10.6, and 3.5%. A continuous measure of childhood gender nonconformity (CGN) was sensitive to slight variations in homosexual attraction and behavior. In particular, among both men and women who identified as heterosexual, there were significant differences between complete heterosexuals and those who admitted to only one or a few same-sex behaviors but no homosexual attraction. Among men, CGN scores distinguished between heterosexuals who admitted to same-sex behavior only and those who admitted to some homosexual attraction. The sexual subgroups also differed on a measure of gender atypicality in adulthood. Implications for developmental theories of sexuality are discussed.     

Patterns of Sexual Arousal in Homosexual,Bisexual, and Heterosexual Men

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 to bisexual erotic material, while this stimulus would induce relatively low levels of response in heterosexual and homosexual men. A sample of 59 men (19 homosexual, 13 bisexual, and 27 heterosexual) were presented with a series of 4-min sexual videos while their genital and subjective sexual responses were measured continuously. Bisexual men did not differ significantly in their responses to male homosexual stimuli (depicting men engaging in sex) from homosexual men, and they did not differ significantly in their responses to heterosexual (depicting two women, without same-sex contact, engaged in sex with a man) and lesbian (depicting women engaging in sex) stimuli from heterosexual men. However, bisexual men displayed significantly higher levels of both genital and subjective sexual arousal to a bisexual stimulus (depicting a man engaged in sex with both a man and a woman) than either homosexual or heterosexual men. The findings of this study indicate that bisexuality in men is associated with a unique and specific pattern of sexual arousal.     

Shape Differences Between the Faces of Homosexual and Heterosexual Men

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 shape between heterosexual and homosexual men. Further, we tested whether self-reported sexual orientation correlated with sexual orientation and masculinity–femininity attributed from facial images by independent raters. In Study 1, we used geometric morphometrics to test for differences in facial shape between homosexual and heterosexual men. The analysis revealed significant shape differences in faces of heterosexual and homosexual men. Homosexual men showed relatively wider and shorter faces, smaller and shorter noses, and rather massive and more rounded jaws, resulting in a mosaic of both feminine and masculine features. In Study 2, we tested the accuracy of sexual orientation judgment from standardized facial photos which were assessed by 80 independent raters. Binary logistic regression showed no effect of attributed sexual orientation on self-reported sexual orientation. However, homosexual men were rated as more masculine than heterosexual men, which may explain the misjudgment of sexual orientation. Thus, our results showed that differences in facial morphology of homosexual and heterosexual men do not simply mirror variation in femininity, and the stereotypic association of feminine looking men as homosexual may confound judgments of sexual orientation.     

A Possible Second Type of Maternal–Fetal Immune Interaction Involved in Both Male and Female Homosexuality

Recent research has found that the mothers of firstborn homosexual sons produce fewer subsequent offspring than do the mothers of firstborn heterosexual sons. It was hypothesized that a subset of mothers of firstborn homosexuals may be responsible for this finding. If there is a subset of mothers whose immune reactions cause their first male fetus to be homosexual and their subsequent fetuses to die, then their immune reactions should also cause their first male fetus to have a lower birth weight. This leads to the prediction that, within the population of firstborn homosexual men, those with no younger siblings should also tend to have lower birth weights. This prediction was tested using a previously published sample of 1,445 firstborn subjects: 929 heterosexual females, 47 homosexual females, 409 heterosexual males, and 60 homosexual males. The results showed that firstborn homosexuals with no younger siblings (i.e., only children) did have lower birth weights compared with all the other subjects, but the finding applied to firstborn lesbian women as well as firstborn gay men.     

Gender-Related Traits of Heterosexual and Homosexual Men and Women

Two studies investigated the relation between sexual orientation and gender-related traits. Analyzing data from an Internet survey, Study 1 found that gay men and lesbians differed from same-sex heterosexuals most strongly on gender diagnosticity (GD) measures, which assess male- versus female-typicality of occupational preferences (effect sizes were 1.14 for men and 0.53 for women) and least strongly on instrumentality (I) and expressiveness (E). Study 2 found that GD measures showed large differences between 289 gay and 200 heterosexual men (d = 0.95) and between 296 lesbian and 435 heterosexual women (d = 1.32), whereas I and E showed much smaller differences. In Study 2 homosexual–heterosexual diagnosticity measures, computed from men's and women's occupational preferences, correlated very strongly with GD measures (r = 0.88 for men and 0.89 for women), indicating that occupational preference items that distinguished men from women also tended to distinguish heterosexual from homosexual individuals. LISREL 8 analyses showed that self-ascribed masculinity–femininity did not mediate the strong relation between sexual orientation and GD for men or for women.