scholarly journals Kisspeptin Expression in the Human Infundibular Nucleus in Relation to Sex, Gender Identity, and Sexual Orientation

2016 ◽  
Vol 101 (6) ◽  
pp. 2380-2389 ◽  
Author(s):  
Melanie Taziaux ◽  
Annemieke S. Staphorsius ◽  
Mohammad A. Ghatei ◽  
Stephen R. Bloom ◽  
Dick F. Swaab ◽  
...  
Keyword(s):  
Sexual Orientation ◽  
Sex Difference ◽  
Sexual Differentiation ◽  
Animal Studies ◽  
Outcome Measure ◽  
Sex Reversal ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
Brain Sexual Differentiation ◽  
Male To Female

Abstract Context: Since the discovery of its central role in reproduction, our functional neuroanatomical knowledge of the hypothalamic kisspeptin system is predominantly based on animal studies. Although sex differences in kisspeptin expression have been shown in humans in adulthood, the developmental origin of this sex difference is unknown. Objectives: Our objectives were to determine the following: 1) when during development the sex difference in kisspeptin expression in the infundibular nucleus would emerge and 2) whether this sex difference is related to sexual orientation or transsexuality. Design and Setting: Postmortem hypothalamic tissues were collected by The Netherlands Brain Bank, and sections were stained for kisspeptin by immunohistochemistry. Patients: Hypothalami of 43 control subjects were categorized into three periods: infant/prepubertal (six girls, seven boys), adult (11 women, seven men), and elderly (six aged women, six aged men). Eight male-to-female (MTF) transsexuals, three HIV+ heterosexual men, and five HIV+ homosexual men were also analyzed. Main Outcome Measure: We estimated the total number of kisspeptin-immunoreactive neurons within the infundibular nucleus. Results: Quantitative analysis confirmed that the human infundibular kisspeptin system exhibits a female-dominant sex difference. The number of kisspeptin neurons is significantly greater in the infant/prepubertal and elderly periods compared with the adult period. Finally, in MTF transsexuals, but not homosexual men, a female-typical kisspeptin expression was observed. Conclusions: These findings suggest that infundibular kisspeptin neurons are sensitive to circulating sex steroid hormones throughout life and that the sex reversal observed in MTF transsexuals might reflect, at least partially, an atypical brain sexual differentiation.

Testing the McBeath Hypothesis: Relation of Sexual Orientation and Belief in the Paranormal

1997 ◽  
Vol 81 (3) ◽  
pp. 890-890
Author(s):  
Michael A. Thalbourne
Keyword(s):  
Sexual Orientation ◽  
Forced Choice ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
Australian Sheep

According to McBeath, the incidence of homosexuality among experients of paranormal phenomena exceeds that which would be expected by chance. Therefore, 50 homosexual men and 50 heterosexual men were administered the forced-choice version of the 18-item Australian Sheep-Goat Scale as a measure of belief in and alleged experience of the paranormal. As no differences were found in scores on belief/experience, there was no evidence for McBeath's hypothesis.

scholarly journals Sexual Orientation and Neuroanatomy: An MRI Study of Gray Matter Differences in Homosexual, Bisexual, and Heterosexual Women and Men

2021 ◽  
Author(s):  
Victoria Klimaj ◽  
Adam Safron ◽  
David Sylva ◽  
A.M. Rosenthal ◽  
Meng Li ◽  
...  
Keyword(s):  
Sex Differences ◽  
Sexual Orientation ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
Bisexual Women ◽  
Brain Areas ◽  
Whole Brain ◽  
Men And Women ◽  
Heterosexual Women ◽  
Subcortical Volumes

In this study, we attempted to replicate past work focusing on differences in neuroanatomical structures between heterosexual and homosexual men and women. We also performed the first analyses of sexual orientation and neuroanatomy to include bisexual men and women. Sex differences in raw subcortical volumes were consistent with past work and a broader literature on sex differences, showing larger raw subcortical volumes in male groups than female groups. However, we did not confirm past findings showing larger raw volumes in heterosexual than in homosexual men in the left thalamus or right thalamus. Additionally, we did not confirm past findings showing thicker cortices in heterosexual men than in homosexual men in visual/occipital areas (right cuneus, right lingual gyrus, right pericalcarine cortex) or a frontal area (right pars triangularis). Exploratory whole-brain analyses revealed several areas of difference between women that may be of interest for future confirmatory research. Bisexual women had smaller volumes in a region of the olfactory tubercule than heterosexual women as well as a thicker right anterior insula region than homosexual women. Homosexual women had smaller volumes in regions of the inferior parietal lobule (IPL) than both heterosexual women and bisexual women. The functional relevance of these brain areas in terms of understanding female sexual orientation is unclear. However, based on these areas, future work may wish to consider the potential social, emotional, attentional, interoceptive, or general reward-related characteristics that may differentiate women with different attraction patterns. In contrast to previous work, no differences were found between groups of men (heterosexual, bisexual, or homosexual) in any of our analyses. Finally, in terms of whole-brain analyses of sex differences, heterosexual women had both thicker cortices and larger (relative to the whole brain) gray matter volume than heterosexual men in the superior frontal gyrus, in contrast to large-scale studies of sex difference. Although statistically significant at a stringent threshold (FWE-corrected), our whole-brain findings should be interpreted and generalized with caution. The heterogeneity of patterns across analyses of sexual orientation and brain structure (and even across studies of sex/gender and brain structure) suggests that findings may potentially depend upon particular sample characteristics, and potentially Type 1 error due to the testing of many different brain areas.

Formation of homosexual orientation of men in adolescence

2014 ◽  
Vol 45 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Grażyna Katra
Keyword(s):  
Sexual Orientation ◽  
Young Adult ◽  
Comparative Study ◽  
Sexual Identity ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
Main Hypothesis ◽  
Homosexual Orientation ◽  
Personal Attitudes ◽  
Interview Questionnaire

Abstract The aim of the study was to explore the experiences of homosexual men connected with the formation of their sexual orientation in adolescence. A comparative study of 27 young adult homosexual men and 28 heterosexual men of similar age used a categorised interview questionnaire consisting of two parts: the first with questions regarding sexual dreams, fantasies and erotic encounters; the second with questions on family and social circumstances. The study yielded an abundance of interesting data on the psychological circumstances of homosexual men during the formation of sexual orientation and its awareness as well as differences and similarities in that area between homosexual and heterosexual men. For instance, it revealed experience patterns concerning the formation of sexual identity and personal attitudes toward one’s sexual orientation characteristic of homosexual persons. The study verified the main hypothesis that mental-internal experiences precede behavioural-external ones both in homosexual and heterosexual persons.

scholarly journals Male sexual orientation, gender nonconformity, and neural activity during mental rotations: an fMRI study

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Monika Folkierska-Żukowska ◽  
Qazi Rahman ◽  
Artur Marchewka ◽  
Marek Wypych ◽  
Dawid Droździel ◽  
...  
Keyword(s):  
Sexual Orientation ◽  
Mental Rotation ◽  
Gay Men ◽  
Sex Difference ◽  
Neural Correlates ◽  
Gender Nonconformity ◽  
Angular Gyrus ◽  
Heterosexual Men ◽  
Gender Nonconforming ◽  
Superior Frontal Gyrus

Abstract The cross-sex shift hypothesis predicts that gay men should perform more like heterosexual women on important neurocognitive tasks on which men score higher than women, such as mental rotation. Studies also suggest sex differences exist in the neural correlates of mental rotation. However, no studies have taken sexual orientation into account or considered within-group variation attributable to recalled gender nonconformity (a developmental trait reliably associated with human nonheterosexuality). We quantified the neural correlates of mental rotation by comparing two groups of gay men, gender conforming (n = 23) and gender nonconforming (n = 23), to gender conforming heterosexual men (n = 22) and women (n = 22). We observed a sex difference between heterosexual men and women in the premotor cortex/supplementary motor cortex and left medial superior frontal gyrus. We also observed a sex difference as well as a cross-sex shift in gay men who recalled being gender nonconforming as children in the right superior frontal gyrus, right angular gyrus, right amygdala/parahippocampal gyrus, and bilaterally in the middle temporal gyrus and precuneus. Thus, cross-sex shifts may be associated with underlying developmental factors which are associated with sexual orientation (such as gender nonconformity). The results also suggest that gay men should not be studied as a homogenous group.

Birth Order among Homosexual Men

2003 ◽  
Vol 92 (1) ◽  
pp. 117-118 ◽  
Author(s):  
Kenneth J. Zucker ◽  
Ray Blanchard ◽  
Marvin Siegelman
Keyword(s):  
Sexual Orientation ◽  
Birth Order ◽  
Empirical Research ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
Null Finding

Nicolosi and Byrd in 2002 summarized empirical research on birth order and sexual orientation in men, which research has documented that homosexual men have a later birth order than heterosexual men. They did not, however, note a more refined analysis of an earlier null finding by Siegelman. This 1998 reanalysis by Blanchard, Zucker, Siegelman, Dickey, and Klassen also confirmed the later birth order of homosexual men.

Birth Order and Sibling Sex Ratio in Relation to Sexual Orientation in China

2014 ◽  
Vol 42 (6) ◽  
pp. 995-1001 ◽  
Author(s):  
Yin Xu ◽  
Yong Zheng
Keyword(s):  
Sexual Orientation ◽  
Sex Ratio ◽  
Birth Order ◽  
Cultural Context ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
Heterosexual Women ◽  
Chinese Parents ◽  
Older Brothers ◽  
Sibling Sex Ratio

We examined birth order and sibling sex ratio in relation to sexual orientation within a Chinese cultural context. A total of 672 people comprising 160 heterosexual men, 215 homosexual men, 255 heterosexual women, and 42 homosexual women, took part in a web-based survey. Our results showed that as a whole homosexual and heterosexual men had a significantly late position in the birth order of the children in their families, but that the same phenomenon did not apply for homosexual women. In contrast to studies involving Western populations, in this study heterosexual and homosexual men had a significant excess of older sisters, but not older brothers when compared with the norm in a Chinese population. We concluded that the male-preference stopping rule adopted by Chinese parents affected birth order and sibling sex ratio in relation to sexual orientation.

scholarly journals Are homosexual males a risk group for hepatitis A infection in intermediate endemicity areas?

1996 ◽  
Vol 117 (1) ◽  
pp. 145-148 ◽  
Author(s):  
J. Ballesteros ◽  
R. Dal-Ré ◽  
A. González ◽  
J. Del Romero
Keyword(s):  
Sexual Orientation ◽  
Sexually Transmitted Diseases ◽  
Odds Ratio ◽  
Hepatitis A ◽  
Risk Group ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
Sexually Transmitted ◽  
Increased Risk ◽  
Intermediate Endemicity

SummaryThe purpose of this study was to examine the prevalence of antibody against hepatitis A (anti-HAV) in a population of homosexual men compared with that of heterosexual men in an area of intermediate HAV endemicity (Madrid, Spain). A total of 148 patients were recruited in a Sexually Transmitted Diseases Clinic: 74 homosexuals (mean age of 28±5 years) and 74 heterosexuals (29±5 years). The prevalence of anti-HAV antibody was 47% and 43% for homo-and heterosexuals, respectively. Among the factors evaluated (age, sexual orientation and practices, travel to high HAV endemicity areas) oral-anal contact was significantly associated with a higher prevalence of anti-HAV antibody (odds ratio, 2·8; 95% confidence interval, 1·1–7·4;P= 0·03). These results indicated that in an area of intermediate endemicity young homosexual men are not at increased risk of having acquired hepatitis A infection than heterosexuals. Oral–anal contact is an independent risk factor that influences the presence of anti-HAV antibody, regardless of sexual orientation.

Who are gynandromorphophilic men? Characterizing men with sexual interest in transgender women

2015 ◽  
Vol 46 (4) ◽  
pp. 819-827 ◽  
Author(s):  
K. J. Hsu ◽  
A. M. Rosenthal ◽  
D. I. Miller ◽  
J. M. Bailey
Keyword(s):  
Sexual Orientation ◽  
Sexual Arousal ◽  
Sexual Attraction ◽  
Sexual Interest ◽  
Transgender Women ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
Male And Female ◽  
Erotic Stimuli ◽  
Subjective Sexual Arousal

BackgroundGynandromorphophilia (GAMP) is sexual interest in gynandromorphs (GAMs; colloquially, shemales). GAMs possess a combination of male and female physical characteristics. Thus, GAMP presents a challenge to conventional understandings of sexual orientation as sexual attraction to the male v. female form. Speculation about GAMP men has included the ideas that they are homosexual, heterosexual, or especially, bisexual.MethodWe compared genital and subjective sexual arousal patterns of GAMP men with those of heterosexual and homosexual men. We also compared these groups on their self-ratings of sexual orientation and sexual interests.ResultsGAMP men had arousal patterns similar to those of heterosexual men and different from those of homosexual men. However, compared to heterosexual men, GAMP men were relatively more aroused by GAM erotic stimuli than by female erotic stimuli. GAMP men also scored higher than both heterosexual and homosexual men on a measure of autogynephilia.ConclusionsResults provide clear evidence that GAMP men are not homosexual. They also indicate that GAMP men are especially likely to eroticize the idea of being a woman.

EXPECTATIONS OF ROMANTIC RELATIONSHIPS: A COMPARISON BETWEEN HOMOSEXUAL AND HETEROSEXUAL MEN WITH REGARD TO BAXTER'S CRITERIA

1999 ◽  
Vol 27 (4) ◽  
pp. 363-374 ◽  
Author(s):  
Charlotte Bäccman ◽  
Per Folkesson ◽  
Torsten Norlander
Keyword(s):  
Sexual Orientation ◽  
Romantic Relationships ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
The Individual ◽  
The Right ◽  
The Relationship

According to Baxter (1986) every relationship has rules which must be followed. If at least one of these rules is broken, it gives the individual the right to breakup the relationship. Baxter identified eight such rules or criteria. The aim of the present study was to investigate whether or not the expectations of romantic relationships held by homosexual men can be linked to Baxter's criteria. Data were obtained through a questionnaire addressed to 31 homosexual men and 50 heterosexual men. Results indicated that Baxter's criteria can be linked to expectations of romantic relationships held by men regardless of sexual orientation, and that age and experience are more reliable predictors than is sexual orientation.

scholarly journals Sexual orientation and health behaviors among college students in Italy

Genus ◽  
2021 ◽  
Vol 77 (1) ◽  
Author(s):  
Maria Sironi ◽  
Julie Fricke
Keyword(s):  
College Students ◽  
Sexual Orientation ◽  
Health Behaviors ◽  
Heterosexual Men ◽  
Homosexual Men ◽  
Bisexual Men ◽  
Bisexual Women ◽  
Emotional Life ◽  
Data Set ◽  
Heterosexual Women

AbstractStudies regarding sexual orientation and health behaviors have largely neglected the Italian context. This research utilizes the second wave of the ‘Sexual and Emotional Life of Youths’ (SELFY) data set to compare the health behaviors of sexual minority (SM) and heterosexual college students in Italy. Results showed that bisexual women were more likely than heterosexual women to smoke both 1–7 and 8+ cigarettes per day, get drunk sometimes and often/very often, and use marijuana and/or ecstasy sometimes and often/very often. Homosexual women were more likely than heterosexual women to smoke 1–7 cigarettes per day, get drunk often/very often, and use marijuana and/or ecstasy often/very often. Homosexual men were more likely than heterosexual men to smoke 8+ cigarettes per day, but less likely to get drunk often/very often. Bisexual men were less likely than heterosexual men to participate in physical activity sometimes, often, and very often. Finally, bisexual men were less likely to exercise often than homosexual men. This work highlights that SM college students in Italy, particularly women, are more likely to engage in specific risky health behaviors compared to their heterosexual counterparts. More attention needs to be given to SMs in Italy to inform the Italian national health care system and to ensure that the appropriate care can be provided when required.

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