Doug P. Vanderlaan

University of Toronto | U of T · Department of Psychology at Mississauga

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 helping to uncover the processes that contribute to sexual orientation development. Research in this field has relied on a variety of populations,...

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, includi...

Background: A younger age at sexual intercourse has frequently been linked to adverse sexual health outcomes. Yet, little is known about its associations with healthy sexual function, and less still about the timing of pre-coital sexual debuts and adult sexual health. Aim: We examined associations between an earlier sexual debut and subsequent s...

Gender dysphoria (GD) is characterized by distress due to an incongruence between experienced gender and sex assigned at birth. Brain functional connectivity in adolescents who experience GD may be associated with experienced gender (vs. assigned sex) and/or brain networks implicated in own-body perception. Furthermore, sexual orientation may be re...

Childhood gender variance (GV) is associated with autism spectrum disorder (ASD) diagnosis/traits; however, this association has mainly been investigated in clinical samples. An ASD screening measure based on 10 items from the commonly used Child Behavior Checklist (CBCL) might enable investigation of this association in a wider variety of (non-cli...

Gender differences in experience of first intercourse are among the largest in sexuality research, with women recalling less pleasure and satisfaction than men. This "enjoyment gap" has not been considered in explanations of gender differences in sexual desire. Yet, reinforcement and incentive learning features prominently in recent models of women...

Gender and sexually diverse adolescents have been reported to be at an elevated risk for suicidal thoughts and behaviors. For transgender adolescents, there has been variation in source of ascertainment and how suicidality was measured, including the time-frame (e.g., past 6 months, lifetime). In studies of clinic-referred samples of transgender ad...

Current understanding of how culture relates to the development of children's gender-related peer preferences is limited. To investigate the role of societal acceptance of gender nonconformity, this study compared children from China and Thailand. Unlike China and other cultures where the conceptualization of gender as binary is broadly accepted, i...

The biodevelopment of psychological sex differentiation is putatively reflected in several anthropometrics. We examined eight anthropometrics in 1404 Thai participants varying in sex, sexual orientation, and gender identity/expression: heterosexual men and women, gay men, lesbian women, bisexual women, sao praphet song (transgender birth-assigned m...

Neurohormonal theory argues that organizational effects of hormone exposure influence sexual orientation and gender identity, as well as sex differences in visuospatial cognition. This study examined mental rotation task (MRT) performance in a diverse Thai sample (N = 980). Thai culture has several third genders: individuals assigned male at birth...

Asexuality is defined as a unique sexual orientation characterized by a lack of sexual attraction to others. This has been challenged, with some experts positing that it is better explained as a sexual dysfunction. Sexual Interest/Arousal Disorder (SIAD) is characterized by absent/reduced sexual interest/arousal paired with personal distress, with...

Male androphilia (i.e., male sexual attraction to adult males) is considered an evolutionary paradox because it is partially influenced by genes and associated with decreased reproduction. Traits associated with attachment to genetic relatives (i.e., kin) could prompt increased kin-directed altruism, thereby offsetting decreased reproduction by hel...

No study to date has simultaneously tested how poor peer relations, generic risk factors, and parental attitudes impact the behavioral and emotional challenges of children who vary in their gender expression. In a community sample, the present study investigated various hypothesized psychosocial and generic risk factors regarding the association be...

The funding information stated for Bin Zuo (BZ) in the Acknowledgements of this article as originally published was incorrect.

From a young age, children’s peer appraisals are influenced by the social categories to which peers belong based on factors such as race and gender. To date, research regarding the manner in which race- and gender-related factors might interact to influence these appraisals has been limited. The present study employed an experimental vignette parad...

Gender dysphoria (GD) is characterized by distress due to an incongruence between experienced gender and sex assigned at birth. Sex-differentiated brain regions are hypothesized to reflect the experienced gender in GD and may play a role in sexual orientation development. Magnetic resonance brain images were acquired from 16 GD adolescents assigned...

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 simultaneousl...

Human same-sex sexual attraction is considered to be an evolutionary paradox. This paradox rests on same-sex attracted individuals having lowered direct reproduction, indicating reduced direct fitness of genes that influence same-sex attraction. Yet, relatively few empirical studies have examined the relation between same-sex sexual attraction and...

Children display intergroup bias in relation to gender. The present study examined whether children’s self-perceived same- and other-gender similarity were related to their same- and other-gender positivity and negativity, respectively. Children aged 6–10 years (N = 149) were interviewed about their self-perceived similarity to girls and to boys an...

Past research has linked poor psychosocial adjustment among children who express gender nonconformity (GNC) to poor peer relations (e.g., facing ridicule and rejection); however, very little research has explored whether it is possible to improve children’s appraisals of GNC. The present study attempted to replicate a previous intervention that was...

Darwinian sexual selection theory holds that mate selection occurs inter-sexually, and mate competition occurs intra-sexually for opposite-sex partners. We demonstrate that inter-sexual mate competition can also occur among humans at appreciable rates that vary by culture. In Canada, inter-sexual mate competition was both rare and inconsequential....

Previous research suggests that people from different cultures weigh cues in the eyes versus mouth differently while interpreting emotions. In Western cultures, where overt emotional display is the norm, people weigh the mouth region more heavily when interpreting facial emotional expression in comparison with people from Eastern cultures. By contr...

Background Adolescents with low self-esteem often experience internalizing psychopathology (i.e., anxiety, depression). Self-esteem may therefore be a clinically relevant construct for assessment and treatment outcomes. We examined whether general and domain-specific (family, peer, academic) self-esteem are related to adolescents’ internalizing sym...

Past research suggests that children have biased negative appraisals of gender-variant (GV) peers (i.e., peers who display behaviors/interests that do not align with gender stereotypes). In the current study, Canadian cisgender 4- and 5-year-olds and 8- and 9-year-olds (N = 183; 48.6% girls), who were ethnically diverse (36% White European heritage...

Androphilia refers to sexual attraction toward adult males. Androphilic males’ female genetic relatives might offset the fitness cost of androphilia by having elevated numbers of offspring. Increased attractiveness relative to other women may enable these females to marry up the social hierarchy, providing greater access to resources to support mor...

The fraternal birth order effect (FBOE) is the finding that older brothers increase the probability of homosexuality in later-born males, and the female fecundity effect (FFE) is the finding that the mothers of homosexual males produce more offspring than the mothers of heterosexual males. In a recent paper, Khovanova proposed a novel method for co...

In clinical child and retrospective adult samples, childhood gender variance (GV; i.e., cross-gender behaviour) has been associated with separation anxiety (SA; i.e., distress related to separation from attachment figures) in males. This study examined GV and SA in a nonclinical sample of 892 boys and 933 girls aged 6–12 years via parent-reports. P...

Objective: Studies of children with gender dysphoria (GD) have reported an overrepresentation of autism spectrum disorder (ASD) or traits. One limitation of these studies has been the absence of a concurrent comparison group of children referred for other clinical problems. The present study addressed this gap by comparing 61 children referred for...

Gender-nonconforming children are often perceived less positively, which may harm their well-being. We examined the development of such perceptions and an intervention to modify them. Chinese children’s appraisals were assessed using multiple measures (verbal responses, sharing, and rank order task) after viewing vignettes of gender-conforming (GC...

Significance Studying individual differences in gender and sexual orientation provides insight into how early-life biology shapes brain and behavior. The literature identifies multiple biodevelopmental influences on male sexual orientation, but these influences are generally studied individually, and the potential for association or interaction bet...

Identifying and quantifying sex differences and similarities has been a central research question and fascinated scientists for centuries. A large body of work has been accumulated on this topic; however, conclusions are often drawn as if they are applicable across cultures even though studies have predominantly relied on Western samples. This chap...

Gender variance (GV) and autism spectrum disorder (ASD) frequently co-occur in clinical populations. We investigated GV in association with ASD characteristics in nonclinical children and in children with developmental/mental health diagnoses. In 6–12-year-olds (N = 2445; 51% birth-assigned boys), the Gender Identity Questionnaire for Children meas...

Developmental theories of sexual orientation largely center on sexual differentiation processes. One hypothesis is that low prenatal androgens are associated with same-sex attraction in men. Using indirect measures of androgens (e.g., height, weight, pubertal onset), this hypothesis has received mixed support, suggesting there may be subgroups of g...

Previous clinical research on children who experience gender dysphoria has demonstrated links between marked childhood gender variant behaviour and several variables thought to provide a window on biological processes affecting brain sexual differentiation during the pre-/perinatal period. These variables include handedness, birth order, and birth...

Androphilia is associated with an elevated number of older brothers among natal males. This association, termed the fraternal birth order effect, has been observed among gay men who exhibit marked gender nonconformity. Gender nonconformity has been linked to gay men's preferred anal sex role. The present study investigated whether these two lines o...

Previous studies examining the associations between women’s sexual orientation and mental health have obtained inconsistent results. Whereas some studies have suggested that status as a lesbian or bisexual woman may be associated with greater mental health risk, others have suggested that bisexual women may be specifically vulnerable to mental heal...

Objective: To examine childhood gender nonconformity (GNC) and psychological well-being in a community-based sample using measures that bridge clinical and nonclinical literature. Method: Caregivers reported on the GNC (Gender Identity Questionnaire for Children [GIQC]) and behavioral and emotional problems (Child Behavior Checklist [CBCL]) of t...

We conducted a direct test of an immunological explanation of the finding that gay men have a greater number of older brothers than do heterosexual men. This explanation posits that some mothers develop antibodies against a Y-linked protein important in male brain development, and that this effect becomes increasingly likely with each male gestatio...

The current study evaluated the possibility that greater negative mental health outcomes reported among gay, lesbian, and gender-atypical individuals, compared to gender-typical individuals, are present in childhood and persist into adulthood. Sex and sexual orientation differences in self-reported adulthood and recalled childhood indicators of dep...

This study evaluated the presence of clinical range behavior problems and psychiatric diagnoses in 25 girls referred for Gender Identity Disorder (GID) in childhood (M age, 8.88 years) at the time of follow-up in adolescence or adulthood (M age, 23.2 years). At follow-up, three (12%) of the girls were judged to have persistent GID based on DSM-IV c...

Having a greater than average number of older biological brothers is a robust correlate of male androphilia (i.e., sexual attraction and arousal to adult males). Previous investigations have sought to understand whether this fraternal birth order (FBO) effect is also systematically related to recalled indicators of childhood gender nonconformity (C...

Developmental theories of the biological basis of sexual orientation suggest that sexually differentiated psychological and behavioural traits should be linked with sexual orientation. Subgroups of gay men delineated by anal sex roles differ according to at least one such trait: gender expression. The present study assessed the hypothesis that hand...

Read-only version of article available at: http://rdcu.be/l2wf ABSTRACT: The sexually antagonistic gene hypothesis (SAGH) for male androphilia posits that genes associated with androphilia (i.e., sexual attraction to adult males) will result in lowered reproduction when present in males, but increased reproduction when present in females. Findings...

Androphilia refers to sexual attraction toward adult males, whereas gynephilia refers to sexual attraction toward adult females. The kin selection hypothesis posits that androphilic males help kin increase their reproductive output via kin-directed altruism, thus offsetting their own lowered reproduction and contributing to the fitness of genes und...

Previous research has indicated that biological older brothers increase the odds of androphilia in males. This finding has been termed the fraternal birth order effect . The maternal immune hypothesis suggests that this effect reflects the progressive immunization of some mothers to male-specific antigens involved in fetal male brain masculinizatio...

For adolescents with gender dysphoria, it has become common to be offered hormonal treatment to either delay or suppress pubertal development and/or to masculinize or feminize the body. At the same time, it has been our clinical impression that the psychological vulnerability of at least some of these youth has been overlooked. Fifty consecutive re...

Previous research established that male androphilia (i.e., sexual arousal and attraction to adult males) clusters in families. Some studies find that male androphilia clusters in both the paternal and maternal lines, while others find that it clusters only in the latter. Most of the research investigating the familial nature of male androphilia has...

Several studies indicate that homosexual males have a high proportion of older brothers compared to heterosexual males. Natal males with gender dysphoria who are likely to be homosexual also display this sibship pattern. Until recently, there was little evidence linking homosexuality and/or gender dysphoria in females to unique sibship characterist...

This study is the third in a series to examine behavioral and emotional problems in children and adolescents with gender dysphoria in a comparative analysis between two clinics in Toronto, Ontario, Canada and Amsterdam, the Netherlands. In the present study, we report Child Behavior Checklist (CBCL) and Youth Self-Report (YSR) data on adolescents a...

Journal of Adolescent Health, 2016, 58, 693-694

Androphilia refers to sexual attraction and arousal toward males whereas gynephilia refers to sexual attraction and arousal toward females. This study tested the adaptive feminine phenotype model of the evolution of male androphilia via kin selection, which posits that the development of an evolved disposition toward elevated kin-directed altruism...

Objective: This study examined rates of self-harm and suicidality (ideation and behavior) in children referred clinically for gender dysphoria compared with their siblings, and referred and nonreferred children from the Child Behavior Checklist (CBCL) standardization sample. Predictors or correlates of self-harm/suicidality were also examined. Me...

Camperio Ciani et al. argued that the Urak-Lawoi people of Ko Lipe island live in a "traditional," "subsistence primitive society" reminiscent of the "ancestral" human past and that their socio-cultural situation is "remarkably similar" to Samoa. On this basis, they asserted that the Ko Lipe Urak-Lawoi are an appropriate population for determining...