The biology of human psychosexual differentiation

Updates on the Care of Cloacal Exstrophy

Cloacal exstrophy is the most severe congenital anomaly of the exstrophy-epispadias complex and is characterized by gastrointestinal, genitourinary, neurospinal, and musculoskeletal malformations. Individualized surgical reconstruction by a multidisciplinary team is required for these complex patients. Not infrequently, patients need staged surgical procedures throughout childhood and adolescence. Following significant improvements in medical care and surgical reconstructive techniques, nearly all patients with cloacal exstrophy now survive, leading to an increased emphasis on quality of life. Increased attention is given to gender identity and the implications of reconstructive decisions. Long-term sequelae of cloacal exstrophy, including functional continence and sexual dysfunction, are recognized, and many patients require ongoing complex care into adulthood.

Carving the Biodevelopment of Same-Sex Sexual Orientation at Its Joints

Sexual orientation is a core aspect of human experience and understanding its development is fundamental to psychology as a scientific discipline. Biological perspectives have played an important role in uncovering the processes that contribute to sexual orientation development. Research in this field has relied on a variety of populations, including community, clinical, and cross-cultural samples, and has commonly focused on female gynephilia (i.e., female sexual attraction to adult females) and male androphilia (i.e., male sexual attraction to adult males). Genetic, hormonal, and immunological processes all appear to influence sexual orientation. Consistent with biological perspectives, there are sexual orientation differences in brain development and evidence indicates that similar biological influences apply across cultures. An outstanding question in the field is whether the hypothesized biological influences are all part of the same process or represent different developmental pathways leading to same-sex sexual orientation. Some studies indicate that same-sex sexually oriented people can be divided into subgroups who likely experienced different biological influences. Consideration of gender expression in addition to sexual orientation might help delineate such subgroups. Thus, future research on the possible existence of such subgroups could prove to be valuable for uncovering the biological development of sexual orientation. Recommendations for such future research are discussed.

IDEA Group Consensus Statement on Medical Management of Adult Gender Incongruent Individuals Seeking Gender Affirmation as Male

Gender-affirming hormone therapy (GAHT) is the most frequent treatment offered to gender-incongruent individuals, which reduces dysphoria. The goal of therapy among gender-incongruent individuals seeking gender affirmation as male is to change their secondary sex characteristics to affect masculine physical appearances. GAHT greatly improves mental health and quality of life among gender incongruent individuals. India-specific guideline for appropriate care for gender-incongruent individuals is almost absent. This document is intended to assist endocrinologists and other healthcare professionals interested in gender incongruity for individuals seeking gender affirmation as male. A safe and effective GAHT regimen aims to effect masculinising physical features without adverse effects. In this document, we offer suggestions based on an in-depth review of national and international guidelines, recently available evidence and collegial meetings with expert Indian clinicians working in this field. Clinicians represented in our expert panel have developed expertise due to the volume of gender incongruent individuals they manage. This consensus statement provides protocols for the hormone prescribing physicians relating to diagnosis, baseline evaluation and counselling, prescription planning for masculinising hormone therapy, choice of therapy, targets for monitoring masculinising hormone therapy, clinical and biochemical monitoring, recommending sex affirmation surgery and peri-operative hormone therapy. The recommendations made in this document are not rigid guidelines, and the hormone-prescribing physicians are encouraged to modify the suggested protocol to address emerging issues.

To What Extent are Prenatal Androgens Involved in the Development of Male Homosexuality in Humans?

Endocrine variations, including possibly reduced exposure to androgens, may contribute to the development of male homosexuality, with animal models demonstrating same-sex mate preference with altered exposure during prenatal or early postnatal development. As similar studies in humans are impossible, indirect physical and cognitive measures of androgen exposure are used. Some studies suggest that physical measures affected by prenatal androgens, including the index-to-ring finger ratio, growth indices, and facial structure, are more "feminine" in gay men. Gay men also exhibit significant childhood gender non-conformity and a "feminized" anatomical and functional brain pattern in sexual arousal, as well as domains such as language, visuospatial skills and hemispheric relationships. However, many of these results are equivocal and may be confounded by other factors. Research has also been hampered by inconsistencies in the reporting of sexual orientation and the potentially unrepresentative populations of gay men studied, while additional complexities pertaining to gender conformity and sexual role may also influence results.

Challenges in the care of transgender and gender-diverse youth: an endocrinologist's view

An increasing number of transgender and gender-diverse (TGD) youth (early pubertal through to late adolescent, typically 9-10 through to 18 years of age) are seeking medical services to bring their physical sex characteristics into alignment with their gender identity - their inner sense of self as male or female or somewhere on the gender spectrum. Compelling research has demonstrated the clear mental health - even life-saving - benefits of gender-affirming care, but current clinical practice guidelines and standards of care are based on only several short-term and a few medium-term outcomes studies complemented by expert opinion. Nevertheless, although the relative paucity of outcomes data raises concerns, the stance of not intervening until more is known is not a neutral option, and large observational studies evaluating current models of care are necessary and are now underway. This Review highlights key advances in our understanding of transgender and gender-diverse youth, the challenges of providing gender-affirming care, gaps in knowledge and priorities for research.

Endocrine disrupting chemicals (EDCs) and the neuroendocrine system: Beyond estrogen, androgen, and thyroid

Hundreds of anthropogenic chemicals occupy our bodies, a situation that threatens the health of present and future generations. This chapter focuses on endocrine disrupting compounds (EDCs), both naturally occurring and man-made, that affect the neuroendocrine system to adversely impact health, with an emphasis on reproductive and metabolic pathways. The neuroendocrine system is highly sexually dimorphic and essential for maintaining homeostasis and appropriately responding to the environment. Comprising both neural and endocrine components, the neuroendocrine system is hormone sensitive throughout life and touches every organ system in the body. The integrative nature of the neuroendocrine system means that EDCs can have multi-system effects. Additionally, because gonadal hormones are essential for the sex-specific organization of numerous neuroendocrine pathways, endocrine disruption of this programming can lead to permanent deficits. Included in this review is a brief history of the neuroendocrine disruption field and a thorough discussion of the most common and less well understood neuroendocrine disruption modes of action. Also provided are extensive examples of how EDCs are likely contributing to neuroendocrine disorders such as obesity, and evidence that they have the potential for multi-generational effects.

Does exogenous androgen use affect the retinal blood flow: An OCTA study in transgender men

PURPOSE

This study aims to investigate the effect of using exogenous androgen on retinal microvascular structures in transgender men.

METHODS

Retinal microvascular structures of transgender men and healthy women in the control group were visualized with optical coherence tomography angiography (OCTA). Foveal avascular zone (FAZ), superficial capillary vascular density (sCVD), deep capillary vascular density (dCVD), and radial peripapillary capillary (RPC) vascular density were evaluated.

RESULTS

Thirty transgender men and 30 healthy women were included in the study. There were no significant differences between transgender men and the control group in terms of FAZ, central macular thickness, parafoveal, and perifoveal retinal thicknesses (p = 0.859, 0.288, 0.561, and 0.719; respectively). sCVD were found to be low in transgender men in the whole image, parafoveal, and perifoveal zones (p = 0.006, 0.025, and 0.005; respectively). Although there were low values of dCVD of the whole image, parafoveal, and perifoveal zones in transgender men, the difference was not statistically significant (p = 0.295, 0.085, and 0.270; respectively). RPC vessel densities in the whole image, peripapillary zone, and the inferior of the optic disc were found to be significantly low in transgender men (p = 0.003, 0.005, and 0.003; respectively).

CONCLUSION

In this study, a decrease in vessel density in the superficial retinal layers and around the optic disc was detected in transgender men. These findings suggest that routine ophthalmological examination may be important in individuals who use exogenous androgens.

Epistemic Injustice in Brain Studies of (Trans)Gender Identity

This study undertakes an analysis of the conceptualization of gender identity in neuroscientific studies of (trans)gender identity that contrast the brains of cisgender and transgender participants. The analysis focuses on instances of epistemic injustice that combine scientific deficiencies and the exclusion of relevant bodies of knowledge. The results of a content analysis show how the ignoring of biosocial, developmental, mosaicist, contextualist, and depathologizing approaches leads to internal conceptual inconsistencies, hermeneutical deficiencies and the upholding of questionable paradigms in the research field. Interviews with researchers involved in these brain studies reveal targeted and diffuse forms of testimonial injustice against alternative approaches, promoted by the hierarchical arrangements of research teams in combination with the careerist and economic logic of research. The analysis points to the exclusion of critical epistemologies of science and the historical oppression of trans people as epistemic agents as the underlying hermeneutical deficiencies.

Providing Inclusive Care for Transgender Patients: Capturing Sex and Gender in the Electronic Medical Record

BACKGROUND

Providing a positive patient experience for transgender individuals includes making the best care decisions and providing an inclusive care environment in which individuals are welcomed and respected. Over the past decades, introduction of electronic medical record (EMR) systems into healthcare has improved quality of care and patient outcomes through improved communications among care providers and patients and reduced medical errors. Promoting the highest standards of care for the transgender populations requires collecting and documenting detailed information about patient identity, including sex and gender information in both the EMR and laboratory information system (LIS).

CONTENT

As EMR systems are beginning to incorporate sex and gender information to accommodate transgender and gender nonconforming patients, it is important for clinical laboratories to understand the importance and complexity of this endeavor. In this review, we highlight the current progress and gaps in EMR/LIS to capture relevant sex and gender information.

SUMMARY

Many EMR and LIS systems have the capability to capture sexual orientation and gender identity (SOGI). Fully integrating SOGI into medical records can be challenging, but is very much needed to provide inclusive care for transgender individuals.

Handedness and Birth Order Among Heterosexual Men, Gay Men, and Sao Praphet Song in Northern Thailand

Previous research has examined handedness and birth order to inform sexual orientation and gender identity/role expression development; however, sexual orientation and gender identity/role expression have rarely been disentangled to provide a more nuanced perspective. In Thailand, we investigated sexual orientation and gender identity simultaneously via comparison of 282 heterosexual men, 201 gay men, and 178 sao praphet song-i.e., androphilic, markedly feminine males recognized as a "third" gender. Handedness was examined as: extremely left-handed, moderately left-handed, ambidextrous, moderately right-handed, or extremely right-handed. Birth order was examined as numbers of older and younger brothers and sisters, by using Berglin's, fraternal, and sororal indices, and by examining the older brother odds ratio and sibling sex ratio. Compared with heterosexual men, gay men and sao praphet song were more likely to be extremely right-handed. Sao praphet song were also more likely to be extremely left-handed than heterosexual and gay men. Heterosexual men and sao praphet song had later sororal birth order compared with the expected Thai population value, suggesting stopping rules influenced when probands' mothers ceased having children. These findings provide new insights and replicate previous findings in a non-Western sample. Regarding handedness, in males, mechanisms related to extreme right-handedness likely influence the development of androphilia, whereas mechanisms related to both extreme right- and extreme left-handedness likely explain the combination of androphilia and feminine gender identity/role expression. Regarding birth order, similar to the conclusions of some prior research, stopping rules pose a challenge for testing the fraternal birth order effect.

Sexual Orientation in Individuals With Congenital Adrenal Hyperplasia: A Systematic Review

Congenital adrenal hyperplasia (CAH) is a genetic condition of the steroidogenic enzymes in the adrenal cortex normally leading to variable degrees of cortisol and aldosterone deficiency as well as androgen excess. Exposure to androgens prenatally might lead to ambiguous genitalia. The fetal brain develops in traditional male direction through a direct action of androgens on the developing nerve cells, or in the traditional female direction in the absence of androgens. This may indicate that sexual development, including sexual orientation, are programmed into our brain structures prenatally. The objective of this study was to perform a systematic review of the literature, investigating sexual orientation in individuals with CAH. The study also aimed at identifying which measures are used to define sexual orientation across studies. The review is based on articles identified through a comprehensive search of the OVIDMedline, PsycINFO, CINAHL, and Web of Science databases published up to May 2019. All peer-reviewed articles investigating sexual orientation in people with CAH were included. Quantitative, qualitative, and mixed methods were considered, as well as self-, parent-, and third-party reports, and no age or language restrictions were enforced on publications. The present review included 30 studies investigating sexual orientation in patients with CAH assigned female at birth (46, XX) (n = 927) or assigned male at birth (46, XY and 46, XX) (n = 274). Results indicate that assigned females at birth (46, XX) with CAH had a greater likelihood to not have an exclusively heterosexual orientation than females from the general population, whereas no assigned males at birth (46, XY or 46, XX) with CAH identified themselves as non-heterosexual. There was a wide diversity in measures used and a preference for unvalidated and self-constructed interviews. Hence, the results need to be interpreted with caution. Methodological weaknesses might have led to non-heterosexual orientation being overestimated or underestimated. The methodological challenges identified by this review should be further investigated in future studies.

A New Theory of Gender Dysphoria Incorporating the Distress, Social Behavioral, and Body-Ownership Networks

When postmortem studies related to transgender individuals were first published, little was known about the function of the various identified nuclei. Now, over 2 decades later, significant progress has been made associating function with specific brain regions, as well as in identifying networks associated with groups of behaviors. However, much of this progress has not been integrated into the general conceptualization of gender dysphoria in humans.

When postmortem studies related to transgender individuals were first published, little was known about the function of the various identified nuclei. Now, over 2 decades later, significant progress has been made associating function with specific brain regions, as well as in identifying networks associated with groups of behaviors. However, much of this progress has not been integrated into the general conceptualization of gender dysphoria in humans. I hypothesize that in individuals with gender dysphoria, the aspects of chronic distress, gender atypical behavior, and incongruence between perception of gender identity and external primary sex characteristics are all directly related to functional differences in associated brain networks. I evaluated previously published neuroscience data related to these aspects and the associated functional networks, along with other relevant information. I find that the brain networks that give individuals their ownership of body parts, that influence gender typical behavior, and that are involved in chronic distress are different in individuals with and without gender dysphoria, leading to a new theory—that gender dysphoria is a sensory perception condition, an alteration in the sense of gender influenced by the reflexive behavioral responses associated with each of these networks. This theory builds upon previous work that supports the relevance of the body-ownership network and that questions the relevance of cerebral sexual dimorphism in regard to gender dysphoria. However, my theory uses a hierarchical executive function model to incorporate multiple reflexive factors (body ownership, gender typical/atypical behavior, and chronic distress) with the cognitive, reflective process of gender identity.

The biological basis of sexual orientation: How hormonal, genetic, and environmental factors influence to whom we are sexually attracted

Humans develop relatively stable attractions to sexual partners during maturation and present a spectrum of sexual orientation from homosexuality to heterosexuality encompassing varying degrees of bisexuality, with some individuals also displaying asexuality. Sexual orientation represents a basic life phenomenon for humans. However, the molecular mechanisms underlying these diverse traits of sexual orientation remain highly controversial. In this review, we systematically discuss recent advancements in sexual orientation research, including those related to measurements and associated brain regions. Current findings regarding sexual orientation modulation by hormonal, genetic, maternal immune system, and environmental factors are summarized in both human and model systems. We also emphasize that future studies should recognize the differences between males and females and pay more attention to minor traits and the epigenetic regulation of sexual orientation. A comprehensive view of sexual orientation may promote our understanding of the biological basis of sex, and that of human reproduction, and evolution.

Gender-Affirming Hormone Therapy for Transgender Men

There are an estimated 1.4 million transgender adults in the United States, and lack of providers knowledgeable in transgender care is a barrier to health care. Obstetricians and Gynecologists can help increase access in part by becoming competent in gender-affirming hormone therapy. For transgender men, testosterone protocols can be extrapolated from those used for hypogonadal cisgender men. Unfortunately, there are not any high-quality, long-term prospective studies on the effectiveness and safety of different testosterone regimens specifically in transgender men, but the available data suggest that gender-affirming testosterone therapy is safe and effective with proper screening and monitoring.

Reduced Luteinizing Hormone Induction Following Estrogen and Progesterone Priming in Female-to-Male Transsexuals

Anatomical studies have suggested that one of the brain structures involved in gender identity is the bed nucleus of the stria terminalis, though this brain structure is probably not the only one to control gender identity. We hypothesized that, if this brain area also affected gonadotropin secretion in humans, transsexual individuals might produce different gonadotropin levels in response to exogenous stimulation. In the present study, we examined whether estrogen combined with progesterone might lead to a change in luteinizing hormone (LH) secretion in female-to-male (FTM) transsexual individuals. We studied female control subjects (n = 9), FTM transsexual subjects (n = 12), and male-to-female (MTF) transsexual subjects (n = 8). Ethinyl estradiol (50 μg/tablet) was administered orally, twice a day, for five consecutive days. After the first blood sampling, progesterone (12.5 mg) was injected intramuscularly. Plasma LH was measured with an immunoradiometric assay. The combination of estrogen and progesterone resulted in increased LH secretion in female control subjects and in MTF subjects, but this increase appeared to be attenuated in FTM transsexual subjects. In fact, the %LH response was significantly reduced in FTM subjects (P < 0.05), but not in MTF subjects (P > 0.5), compared to female control subjects. In addition, the peak time after progesterone injection was significantly delayed in FTM subjects (P < 0.05), but not in MTF subjects (P > 0.5), compared to female control subjects. We then compared subjects according to whether the combination of estrogen and progesterone had a positive (more than 200% increase) or negative (less than 200% increase) effect on LH secretion. A χ² analysis revealed significantly different (P < 0.05) effects on LH secretion between female controls (positive n = 7, negative n = 2) and FTM transsexual subjects (positive n = 4, negative n = 8), but not between female controls and MTF transsexual subjects (positive n = 7, negative n = 1). Thus, LH secretion in response to estrogen- and progesterone priming was attenuated in FTM subjects, but not in MTF subjects, compared to control females. This finding suggested that the brain area related to gender identity in morphological studies might also be involved in the LH secretory response in humans. Thus, altered brain morphology might be correlated to altered function in FTM transsexuals.

Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To update the "Endocrine Treatment of Transsexual Persons: An Endocrine Society Clinical Practice Guideline," published by the Endocrine Society in 2009.

PARTICIPANTS

The participants include an Endocrine Society-appointed task force of nine experts, a methodologist, and a medical writer.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

Group meetings, conference calls, and e-mail communications enabled consensus. Endocrine Society committees, members and cosponsoring organizations reviewed and commented on preliminary drafts of the guidelines.

CONCLUSION

Gender affirmation is multidisciplinary treatment in which endocrinologists play an important role. Gender-dysphoric/gender-incongruent persons seek and/or are referred to endocrinologists to develop the physical characteristics of the affirmed gender. They require a safe and effective hormone regimen that will (1) suppress endogenous sex hormone secretion determined by the person's genetic/gonadal sex and (2) maintain sex hormone levels within the normal range for the person's affirmed gender. Hormone treatment is not recommended for prepubertal gender-dysphoric/gender-incongruent persons. Those clinicians who recommend gender-affirming endocrine treatments-appropriately trained diagnosing clinicians (required), a mental health provider for adolescents (required) and mental health professional for adults (recommended)-should be knowledgeable about the diagnostic criteria and criteria for gender-affirming treatment, have sufficient training and experience in assessing psychopathology, and be willing to participate in the ongoing care throughout the endocrine transition. We recommend treating gender-dysphoric/gender-incongruent adolescents who have entered puberty at Tanner Stage G2/B2 by suppression with gonadotropin-releasing hormone agonists. Clinicians may add gender-affirming hormones after a multidisciplinary team has confirmed the persistence of gender dysphoria/gender incongruence and sufficient mental capacity to give informed consent to this partially irreversible treatment. Most adolescents have this capacity by age 16 years old. We recognize that there may be compelling reasons to initiate sex hormone treatment prior to age 16 years, although there is minimal published experience treating prior to 13.5 to 14 years of age. For the care of peripubertal youths and older adolescents, we recommend that an expert multidisciplinary team comprised of medical professionals and mental health professionals manage this treatment. The treating physician must confirm the criteria for treatment used by the referring mental health practitioner and collaborate with them in decisions about gender-affirming surgery in older adolescents. For adult gender-dysphoric/gender-incongruent persons, the treating clinicians (collectively) should have expertise in transgender-specific diagnostic criteria, mental health, primary care, hormone treatment, and surgery, as needed by the patient. We suggest maintaining physiologic levels of gender-appropriate hormones and monitoring for known risks and complications. When high doses of sex steroids are required to suppress endogenous sex steroids and/or in advanced age, clinicians may consider surgically removing natal gonads along with reducing sex steroid treatment. Clinicians should monitor both transgender males (female to male) and transgender females (male to female) for reproductive organ cancer risk when surgical removal is incomplete. Additionally, clinicians should persistently monitor adverse effects of sex steroids. For gender-affirming surgeries in adults, the treating physician must collaborate with and confirm the criteria for treatment used by the referring physician. Clinicians should avoid harming individuals (via hormone treatment) who have conditions other than gender dysphoria/gender incongruence and who may not benefit from the physical changes associated with this treatment.

Neonatal Sex Assignment in Disorders of Sex Development: A Philosophical Introspection

Management of ambiguous genitalia is highly controversial. This condition was known previously as intersex and presently as disorders of sex development (DSD). There is no consensus regarding the choice, timing and method of sex assignment in neonates with DSD. Consensus conferences could not unify the views of various stakeholders and third parties. This article philosophically examines the nature and origin of such controversies. Misconception, bias and conflicting priorities are identified as the three cardinal sources of controversies. Conceptual duality of sexes, confused notion of sex and gender, bias towards penetrative intercourse, conflict between utopian ideals and reality, unwillingness to compromise are identified as perpetuators of controversies. Suggestions are made regarding sex assignment in various types of DSD based on the understanding of published literature and the author's personal experience.

Prenatal Exposure to Progesterone Affects Sexual Orientation in Humans

Prenatal sex hormone levels affect physical and behavioral sexual differentiation in animals and humans. Although prenatal hormones are theorized to influence sexual orientation in humans, evidence is sparse. Sexual orientation variables for 34 prenatally progesterone-exposed subjects (17 males and 17 females) were compared to matched controls (M age = 23.2 years). A case-control double-blind design was used drawing on existing data from the US/Denmark Prenatal Development Project. Index cases were exposed to lutocyclin (bioidentical progesterone = C₂₁H₃₀O₂; M _W : 314.46) and no other hormonal preparation. Controls were matched on 14 physical, medical, and socioeconomic variables. A structured interview conducted by a psychologist and self-administered questionnaires were used to collect data on sexual orientation, self-identification, attraction to the same and other sex, and history of sexual behavior with each sex. Compared to the unexposed, fewer exposed males and females identified as heterosexual and more of them reported histories of same-sex sexual behavior, attraction to the same or both sexes, and scored higher on attraction to males. Measures of heterosexual behavior and scores on attraction to females did not differ significantly by exposure. We conclude that, regardless of sex, exposure appeared to be associated with higher rates of bisexuality. Prenatal progesterone may be an underappreciated epigenetic factor in human sexual and psychosexual development and, in light of the current prevalence of progesterone treatment during pregnancy for a variety of pregnancy complications, warrants further investigation. These data on the effects of prenatal exposure to exogenous progesterone also suggest a potential role for natural early perturbations in progesterone levels in the development of sexual orientation.

Pubertal Stress and Nutrition and their Association with Sexual Orientation and Height in the Add Health Data

A number of studies have indicated that gay men tend to be shorter, on average, than heterosexual men. Less evidence exists that lesbian women are taller, on average, than heterosexual women. The most popular explanation of the association between sexual orientation and height involves prenatal factors, such that, for example, gay men may have been exposed to lower than typical androgens during fetal development, which impacts their height and sexual orientation as adults. An alternative explanation involves stress, given that stress has been associated with sexual minority identification and with lower height. Another alternative explanation involves nutrition, although its relationship is less clear with sexual minority identification. Using the Add Health data, which is a large, nationally representative and longitudinal sample of American adolescents (n = 14,786), we tested a mediation model, such that sexual orientation → pubertal stress/nutrition → height. Within men, we found that gay men (n = 126) were shorter, on average, than heterosexual men (n = 6412). None of the 24 pubertal stress-related and 15 pubertal nutrition-related variables assessed in the Add Health data mediated the relationship between sexual orientation and height in men. Within women, lesbians (n = 75) did not differ significantly in stature compared to heterosexual women (n = 6267). Thus, prenatal mechanisms (e.g., hormones, maternal immune response) are likely better candidates for explaining the height difference between gay men and heterosexual men.

Sexual Orientation, Objective Height, and Self-Reported Height

Studies that have used mostly self-reported height have found that androphilic men and women are shorter than gynephilic men and women, respectively. This study examined whether an objective height difference exists or whether a psychosocial account (e.g., distortion of self-reports) may explain these putative height differences. A total of 863 participants, recruited at a Canadian university, the surrounding region, and through lesbian, gay, bisexual, and transgender (LGBT) events across Canada, self-reported their height and had their height measured. Androphilic men were shorter, on average, than gynephilic men. There was no objective height difference between gynephilic, ambiphilic, and androphilic women. Self-reported height, statistically controlling for objective height, was not related to sexual orientation. These findings are the first to show an objective height difference between androphilic and gynephilic men. Also, the findings suggest that previous studies using self-reported height found part of a true objective height difference between androphilic and gynephilic men. These findings have implications for existing biological theories of men's sexual orientation development.

Gender identity, gender assignment and reassignment in individuals with disorders of sex development: a major of dilemma

INTRODUCTION

Disorders of Sex Development (DSD) are a wide range of congenital conditions characterized by an incongruence of components involved in sexual differentiation, including gender psychosexual development. The management of such disorders is complex, and one of the most crucial decision is represented by gender assignment. In fact, the primary goal in DSD is to have a gender assignment consistent with the underlying gender identity in order to prevent the distress related to a forthcoming Gender Dysphoria. Historically, gender assignment was based essentially on surgical outcomes, assuming the neutrality of gender identity at birth. This policy has been challenged in the past decade refocusing on the importance of prenatal and postnatal hormonal and genetic influences on psychosexual development.

AIMS

(1) to update the main psychological and medical issues that surround DSD, in particular regarding gender identity and gender assignment; (2) to report specific clinical recommendations according to the different diagnosis.

METHODS

A systematic search of published evidence was performed using Medline (from 1972 to March 2016). Review of the relevant literature and recommendations was based on authors' expertise.

RESULTS

A review of gender identity and assignment in DSD is provided as well as clinical recommendations for the management of individuals with DSD.

CONCLUSIONS

Given the complexity of this management, DSD individuals and their families need to be supported by a specialized multidisciplinary team, which has been universally recognized as the best practice for intersexual conditions. In case of juvenile GD in DSD, the prescription of gonadotropin-releasing hormone analogues, following the World Professional Association for Transgender Health and the Endocrine Society guidelines, should be considered. It should always be taken into account that every DSD person is unique and has to be treated with individualized care. In this perspective, international registries are crucial to improve the understanding of these challenging conditions and clinical practice, in providing a better prediction of gender identity.

A Review of the Status of Brain Structure Research in Transsexualism

The present review focuses on the brain structure of male-to-female (MtF) and female-to-male (FtM) homosexual transsexuals before and after cross-sex hormone treatment as shown by in vivo neuroimaging techniques. Cortical thickness and diffusion tensor imaging studies suggest that the brain of MtFs presents complex mixtures of masculine, feminine, and demasculinized regions, while FtMs show feminine, masculine, and defeminized regions. Consequently, the specific brain phenotypes proposed for MtFs and FtMs differ from those of both heterosexual males and females. These phenotypes have theoretical implications for brain intersexuality, asymmetry, and body perception in transsexuals as well as for Blanchard's hypothesis on sexual orientation in homosexual MtFs. Falling within the aegis of the neurohormonal theory of sex differences, we hypothesize that cortical differences between homosexual MtFs and FtMs and male and female controls are due to differently timed cortical thinning in different regions for each group. Cross-sex hormone studies have reported marked effects of the treatment on MtF and FtM brains. Their results are used to discuss the early postmortem histological studies of the MtF brain.

Scrutinizing Immutability: Research on Sexual Orientation and U.S. Legal Advocacy for Sexual Minorities

We review scientific research and legal authorities to argue that the immutability of sexual orientation should no longer be invoked as a foundation for the rights of individuals with same-sex attractions and relationships (i.e., sexual minorities). On the basis of scientific research as well as U.S. legal rulings regarding lesbian, gay, and bisexual (LGB) rights, we make three claims: First, arguments based on the immutability of sexual orientation are unscientific, given what we now know from longitudinal, population-based studies of naturally occurring changes in the same-sex attractions of some individuals over time. Second, arguments based on the immutability of sexual orientation are unnecessary, in light of U.S. legal decisions in which courts have used grounds other than immutability to protect the rights of sexual minorities. Third, arguments about the immutability of sexual orientation are unjust, because they imply that same-sex attractions are inferior to other-sex attractions, and because they privilege sexual minorities who experience their sexuality as fixed over those who experience their sexuality as fluid. We conclude that the legal rights of individuals with same-sex attractions and relationships should not be framed as if they depend on a certain pattern of scientific findings regarding sexual orientation.

Sexuality in eating disorders patients: etiological factors, sexual dysfunction and identity issues. A systematic review

The scientific community appears to be less interested in sexuality of eating disorders (EDs) as compared to other psychiatric or medical comorbidities. However, a clear association between sexual problems and ED psychopathology was reported from different perspectives. The overarching goal of this systematic review was to evaluate the general approach of the scientific literature toward the topic of sexuality and EDs. In particular, four different categories of research have been individuated, encompassing the role of puberty, and sexual abuse in the pathogenesis of the disorders, sexual dysfunctions, and the association between sexual orientation and EDs psychopathology. Timing of puberty with its hormonal consequences and the changes in the way persons perceive their own body represent a crucial period of life for the onset of the disorder. Sexual abuse, and especially childhood sexual abuse are well-recognized risk factors for the development of ED, determining a worse long-term outcome. Recent research overcome the approach that considers sexual activity of EDs patients, in terms of hypersexuality and dangerous sexual behaviors, considering the sexuality of EDs persons in terms of sexual desire, satisfaction, orgasm and pain. Results from this line of research are promising, and describe a clear relationship between sexual dysfunction and the core psychopathological features of EDs, such as body image disturbances. Finally, the analysis of the literature showed an association between sexual orientation and gender dysphoria with EDs psychopathology and pathological eating behaviors, confirming the validity of research developing new models of maintaining factors of EDs related to the topic of self-identity.

Putative Androgen Exposure and Sexual Orientation: Cross-Cultural Evidence Suggesting a Modified Neurohormonal Theory

INTRODUCTION

According to neurohormonal theory, prenatal androgens are key determinants of sexual orientation. As a reputed marker for prenatal androgens, the 2D:4D finger length ratio has been used in more than a dozen studies to test the hypothesis that prenatal androgens influence sexual orientation. Findings have been very inconsistent.

AIM

The present study sought to retest the hypothesis that 2D:4D and sexual orientation are related is a manner consistent with neurohormonal theory.

METHODS

A 2D:4D measure (of the right hand) along with four additional somatic markers of androgen exposure (height, physical strength, muscularity, and athletic ability) with samples of college students in Malaysia (N = 2,058) and the United States (N = 2,511). The five androgen measures were factor analyzed, resulting in a two-factor solution: Factor 1 consisted of strength, muscularity, and athletic ability (the muscular coordination factor), and Factor 2 was comprised of the r2D:4D and adult height (the bone growth factor).

MAIN OUTCOME MEASURES

Sexual orientation was measured by asking each respondent the extent to which they were sexually attracted to males and the extent to which they were sexually attracted to females, both on 11-point scales.

RESULTS

When the countries and sexes were analyzed separately, neither the r2D:4D measure nor Factor 2 correlated with sexual orientation to significant degrees. Instead, it was the muscular coordination factor that correlated the best. Support was found for the hypothesis that prenatal androgens influence sexual orientation, but the nature of these influences was more complex than neurohormonal theory predicted.

CONCLUSION

A modified theory is needed and presented to accommodate the results from this study.

High Rates of Same-Sex Attraction/Gender Nonconformity in the Offspring of Mothers with Thyroid Dysfunction During Pregnancy: Proposal of Prenatal Thyroid Model

Both youngsters and adults with same-sex attraction are at greater risk for negative health outcomes. Despite mounting efforts to determine the biological background, a satisfactory conclusion has not been reached and there is a need to explore alternate factors like functioning of thyroid system during pregnancy. A retrospective chart review was undertaken of 790 eligible children and adolescents who had been admitted to child psychiatry between 2005 and 2013. This population consisted of 520 (65%) males and 270 (35%) females, aged 8 to 17 years. Fifteen mothers (1.8%) were found to have a history of thyroid dysfunction during pregnancy. Sixteen youngsters (2%) had a history of same-sex attraction. Twelve overlapping cases with both same-sex attraction and maternal thyroid dysfunction during pregnancy were identified, which was extremely significant (P<0.0001, by Fisher’s exact test). The association was also significant for each sex (P<0.0001, by Fisher’s exact test). There is evidence that thyroid gland plays a crucial and decisive role in determining sexual orientation in people. Maternal thyroid dysfunctions during pregnancy may result in homosexual orientation in the offspring.

Perinatal administration of aromatase inhibitors in rodents as animal models of human male homosexuality: similarities and differences

In this chapter we briefly review the evidence supporting the existence of biological influences on sexual orientation. We focus on basic research studies that have affected the estrogen synthesis during the critical periods of brain sexual differentiation in male rat offspring with the use of aromatase inhibitors, such as 1,4,6-androstatriene-3,17 (ATD) and letrozole. The results after prenatal and/or postnatal treatment with ATD reveal that these animals, when adults, show female sexual responses, such as lordosis or proceptive behaviors, but retain their ability to display male sexual activity with a receptive female. Interestingly, the preference and sexual behavior of these rats vary depending upon the circadian rhythm.Recently, we have established that the treatment with low doses of letrozole during the second half of pregnancy produces male rat offspring, that when adults spend more time in the company of a sexually active male than with a receptive female in a preference test. In addition, they display female sexual behavior when forced to interact with a sexually experienced male and some typical male sexual behavior when faced with a sexually receptive female. Interestingly, these males displayed both sexual behavior patterns spontaneously, i.e., in absence of exogenous steroid hormone treatment. Most of these features correspond with those found in human male homosexuals; however, the "bisexual" behavior shown by the letrozole-treated rats may be related to a particular human population. All these data, taken together, permit to propose letrozole prenatal treatment as a suitable animal model to study human male homosexuality and reinforce the hypothesis that human sexual orientation is underlied by changes in the endocrine milieu during early development.

More than just two sexes: the neural correlates of voice gender perception in gender dysphoria

Gender dysphoria (also known as “transsexualism”) is characterized as a discrepancy between anatomical sex and gender identity. Research points towards neurobiological influences. Due to the sexually dimorphic characteristics of the human voice, voice gender perception provides a biologically relevant function, e.g. in the context of mating selection. There is evidence for a better recognition of voices of the opposite sex and a differentiation of the sexes in its underlying functional cerebral correlates, namely the prefrontal and middle temporal areas. This fMRI study investigated the neural correlates of voice gender perception in 32 male-to-female gender dysphoric individuals (MtFs) compared to 20 non-gender dysphoric men and 19 non-gender dysphoric women. Participants indicated the sex of 240 voice stimuli modified in semitone steps in the direction to the other gender. Compared to men and women, MtFs showed differences in a neural network including the medial prefrontal gyrus, the insula, and the precuneus when responding to male vs. female voices. With increased voice morphing men recruited more prefrontal areas compared to women and MtFs, while MtFs revealed a pattern more similar to women. On a behavioral and neuronal level, our results support the feeling of MtFs reporting they cannot identify with their assigned sex.

Click-evoked otoacoustic emissions in children and adolescents with gender identity disorder

Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to originate from elevated levels of testosterone during perinatal sexual differentiation. Therefore, CEOAEs may be used as a retrospective indicator of someone's perinatal androgen environment. Individuals diagnosed with Gender Identity Disorder (GID), according to DSM-IV-TR, are characterized by a strong identification with the other gender and discomfort about their natal sex. Although the etiology of GID is far from established, it is hypothesized that atypical levels of sex steroids during a critical period of sexual differentiation of the brain might play a role. In the present study, we compared CEOAEs in treatment-naïve children and adolescents with early-onset GID (24 natal boys, 23 natal girls) and control subjects (65 boys, 62 girls). We replicated the sex difference in CEOAE response amplitude in the control group. This sex difference, however, was not present in the GID groups. Boys with GID showed stronger, more female-typical CEOAEs whereas girls with GID did not differ in emission strength compared to control girls. Based on the assumption that CEOAE amplitude can be seen as an index of relative androgen exposure, our results provide some evidence for the idea that boys with GID may have been exposed to lower amounts of androgen during early development in comparison to control boys.

Hypothalamic response to the chemo-signal androstadienone in gender dysphoric children and adolescents

The odorous steroid androstadienone, a putative male chemo-signal, was previously reported to evoke sex differences in hypothalamic activation in adult heterosexual men and women. In order to investigate whether puberty modulated this sex difference in response to androstadienone, we measured the hypothalamic responsiveness to this chemo-signal in 39 pre-pubertal and 41 adolescent boys and girls by means of functional magnetic resonance imaging. We then investigated whether 36 pre-pubertal children and 38 adolescents diagnosed with gender dysphoria (GD; DSM-5) exhibited sex-atypical (in accordance with their experienced gender), rather than sex-typical (in accordance with their natal sex) hypothalamic activations during olfactory stimulation with androstadienone. We found that the sex difference in responsiveness to androstadienone was already present in pre-pubertal control children and thus likely developed during early perinatal development instead of during sexual maturation. Adolescent girls and boys with GD both responded remarkably like their experienced gender, thus sex-atypical. In contrast, pre-pubertal girls with GD showed neither a typically male nor female hypothalamic activation pattern and pre-pubertal boys with GD had hypothalamic activations in response to androstadienone that were similar to control boys, thus sex-typical. We present here a unique data set of boys and girls diagnosed with GD at two different developmental stages, showing that these children possess certain sex-atypical functional brain characteristics and may have undergone atypical sexual differentiation of the brain.

Physiology, pathology and pharmacology of the male reproductive system

The male reproductive system consists of the testes, a ductal system and sex accessory organs. Production of sperm by the testes combined with fluids formed by the sex accessory organs (e.g. seminal vesicles, prostate and bulbourethral glands) produce a secretion that supports the survival of spermatozoa and provides a medium through which they can move through the reproductive ducts (e.g. epididymis, vas deferens, ejaculatory duct and urethra) for ejaculation of viable sperm into the female reproductive tract. Summarized herein are the essentials of normal male reproductive physiology, disorders of male sexual differentiation, pharmacological therapy of common diseases of the male genitourinary tract and the impact of drugs of abuse on the male reproductive system.

Twenty years of endocrinologic treatment in transsexualism: analyzing the role of chromosomal analysis and hormonal profiling in the diagnostic work-up

OBJECTIVE

To demonstrate that adequate pubertal history, physical examination, and a basal hormone profile is sufficient to exclude disorders of sexual development (DSD) in adult transsexuals and that chromosomal analysis could be omitted in cases of unremarkable hormonal profile and pubertal history.

DESIGN

Retrospective chart analysis.

SETTING

Endocrine outpatient clinic of a psychiatric research institute.

PATIENT(S)

A total of 475 subjects (302 male-to-female transsexuals [MtF], 173 female-to-male transsexuals [FtM]). Data from 323 (192 MtF/131 FtM) were collected for hormonal and pubertal abnormalities. Information regarding chromosomal analysis was available for 270 patients (165 MtF/105 FtM).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Pubertal abnormalities, menstrual cycle, and hormonal irregularities in relation to chromosomal analysis conducted by karyotype or hair root analysis.

RESULT(S)

In the MtF group, 5.2% of the patients reported pubertal irregularities and 5.7% hormonal abnormalities, and in the FtM group 3.8% and 19.1%, respectively. Overall chromosomal abnormality in both groups was 1.5% (2.9% in the FtM and 0.6% in the MtF group). The aneuploidies found included one gonosomal aneuploidy (45,X[10]/47,XXX[6]/46,XX[98]), two Robertsonian translocations (45,XXder(14;22)(q10;q10)), and one Klinefelter syndrome (47,XXY) that had already been diagnosed in puberty.

CONCLUSION(S)

Our data show a low incidence of chromosomal abnormalities and thus question routine chromosomal analysis at the baseline evaluation of transsexualism, and suggest that it be considered only in cases of abnormal history or hormonal examination.

Review and management of 46,XY disorders of sex development

Disorders of sex development (DSD) among 46,XY individuals are rare and challenging conditions. Abnormalities of karyotype, gonadal formation, androgen synthesis, and androgen action are responsible for the multiple disorders that result in undervirilization during development. Phenotypic appearance and timing of presentation are quite variable. The focus of treatment has shifted from early gender assignment and corrective surgery to careful diagnosis, proper education of patients and their families, and individualized treatment by a multi-disciplinary team. The modern management of these patients is difficult and controversial. Conflicting data on long-term outcomes of these individuals have been reported in the literature. The various etiologies of 46,XY DSD, current approaches to diagnosis and treatment, and reported long-term results are reviewed.

Exploration of functional health, mental well-being and cross-sex hormone use in a sample of Thai male-to-female transgendered persons (kathoeys)

Transgender people sometimes use cross-sex hormones without medical supervision. The use of cross-sex hormones, as well as the functional health and mental well-being, among male-to-female transgendered people ('kathoeys') in Chiang Mai, Thailand, was studied. Sixty kathoeys were interviewed regarding their use of cross-sex hormones and their family relationships. Individuals also completed the Life Orientation Test Revised (LOT-R) to assess dispositional optimism, the Social Functioning Questionnaire (SFQ) and the Short Form Health Survey 36 (SF-36). Three categories were established as follows: those who never cross-dress, those who sometimes cross-dress and those who always cross-dress in public. Of the 60 subjects, 44 had used hormones for prolonged periods (9.7±6.1 years). Their use was related to the permanence of cross-dressing but unrelated to functional health and mental well-being. Fifty percent of subjects had overdosed on commonly used oral contraceptives. Three people used injectable oestrogen in a higher-than-recommended dose. Self-acceptance was high or reasonably good (83%) compared to no acceptance (17%), and neither was related to the permanence of cross-dressing. Their acceptance by parents and siblings was also relatively high (85% and 89%, respectively). The permanence of cross-dressing had no effect on the scores of optimism, SF-36 scores and social functioning. Acceptance by oneself or one's parents did not seem to affect most aspects of functional health and mental well-being, but non-acceptance by siblings generated lower scores on the social functioning and general mental health subscales. Stressors tended to include physical rather than social factors. In conclusion, the unsupervised use of cross-sex hormones was common among kathoeys, and 50% of the sample had overdosed on them. Acceptance was relatively good, except by siblings. New strategies are needed for a more responsible use of cross-sex hormones.

Long-term results of breast reduction in female-to-male transsexuals

Transsexualism is considered to be an extreme end in a large group of gender identity disorders. Two main types of transsexualism are identified: male-to-female (MtF) and female-to-male (FtM). Transsexual persons have a feeling of being incarcerated in a foreign body and therefore they wish to change their sex by hormone therapy and surgical treatment. Breast reduction usually is the first procedure in the process of surgical reassignment in FtM transsexual persons. THE AIM OF THIS STUDY was to evaluate the long-term results of breast reduction in FtM transsexual persons, taking into account breast size and surgical technique. The doctors' and patients' opinions about the results were also compared.

MATERIAL AND METHODS

The study was carried out in a group of 98 FtM transsexual persons treated at the Department of Plastic, Reconstructive and Aesthetic Surgery. Evaluation of the long-term results of breast reduction was performed based on clinical examination done by the doctors and a questionnaire filled in by the patients and the surgeons.

RESULTS

Good results of breast reduction were achieved in more than 60% of the examined patients operated on mainly by Webster technique.

CONCLUSIONS

Clinical examination of the long-term results of breast reduction in FtM transsexual persons revealed good aesthetic effects. The doctors' and the patients' opinions were similar.

Biometric characteristics of the pelvis in female-to-male transsexuals

The objective of the study was to evaluate the metric features of pelvises of 24 female-to-male (FtM) transsexuals as compared to control groups of 24 healthy males and 24 healthy females. The participants had their pelvises X-rayed with the same X-ray apparatus and in the same position. Seventeen measurements were taken on the basis of X-ray pictures of FtM transsexuals' pelvises and both comparison groups. Additionally, their body height was compared. The results showed that FtM transsexuals having female body height represent an intermediate size of three pelvic features and male values of five variables. In order to develop a model based on metric variables of the pelvis that would best discriminate the FtM transsexuals, the control females, and the control males, a discriminant analysis was applied. The model included four variables out of 17 metric features: the height of the pubic symphysis, the greatest pelvic breadth, the interischial distance, and the acetabular diameter. The model was found to be the best in discriminating males from females and FtM transsexuals, but considerably less effective in discriminating transsexuals from the two control groups. The results demonstrate that a number of FtM transsexuals' pelvic measurements reveal "masculinization," which confirms current results demonstrating a shift in the somatometric traits of transsexual females towards male traits. A discriminant analysis based only on pelvic metric features shows some differences between the size of the pelvis and chromosomal sex in FtM transsexuals, which might indicate a biological basis for gender identity disorder.

Sibling sex ratio and birth order in early-onset gender dysphoric adolescents

Several sibship-related variables have been studied extensively in sexual orientation research, especially in men. Sibling sex ratio refers to the ratio of brothers to sisters in the aggregate sibships of a group of probands. Birth order refers to the probands' position (e.g., first-born, middle-born, last-born) within their sibships. Fraternal birth order refers to their position among male siblings only. Such research was extended in this study to a large group of early-onset gender dysphoric adolescents. The probands comprised 94 male-to-female and 95 female-to-male gender dysphoric adolescents. The overwhelming majority of these were homosexual or probably prehomosexual. The control group consisted of 875 boys and 914 girls from the TRAILS study. The sibling sex ratio of the gender dysphoric boys was very high (241 brothers per 100 sisters) compared with the expected ratio (106:100). The excess of brothers was more extreme among the probands' older siblings (300:100) than among their younger siblings (195:100). Between-groups comparisons showed that the gender dysphoric boys had significantly more older brothers, and significantly fewer older sisters and younger sisters, than did the control boys. In contrast, the only notable finding for the female groups was that the gender dysphoric girls had significantly fewer total siblings than did the control girls. The results for the male probands were consistent with prior speculations that a high fraternal birth order (i.e., an excess of older brothers) is found in all homosexual male groups, but an elevated sibling sex ratio (usually caused by an additional, smaller excess of younger brothers) is characteristic of gender dysphoric homosexual males. The mechanisms underlying these phenomena remain unknown.