Origins of Diversity in Gender Expression and Sexual Orientation

We are currently undertaking several cross-cultural studies to investigate the developmental and evolutionary origins of within-sex variation in gender expression and sexual orientation. This research focuses on numerous demographic, physical, and psychological characteristics thought to be influenced by biological mechanisms that act early in development (i.e., prior to or around the time of birth) or are the result of evolutionary processes contributing to the existence of diversity in gender expression and sexual orientation. Through a cross-cultural approach, it is further possible to identify unique sociocultural factors that influence these traits. In both Canada and Thailand, we examine how these characteristics vary according to gender expression and sexual partner preferences, respectively, to give insight into the developmental and evolutionary processes underpinning these traits. In Thailand, we also consider unique “third” gender individuals who do not identify as men or women. These include birth-assigned males who take on a feminine social role (i.e., sao praphet song) as well as birth-assigned females who take on a masculine social role (i.e., tom).

This research is supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant awarded to Dr. VanderLaan and by the University of Toronto Mississauga.

Children’s Concepts of Gender

Young children often have rigid, stereotyped concepts of what makes a person a boy/man or a girl/woman. As a consequence, when they encounter a peer whose behaviour does not fit these rigid stereotypes (e.g., a boy who prefers to have long vs. short hair; a girl who shows a masculine play style), they are likely to respond with ridicule and rejection. This stream of research seeks to better understand how children think about gender, age-related changes in this thinking, and in particular children’s appraisals of other children whose behavior does not conform to gender stereotypes. A major focus of this research stream also includes investigating how we might best limit children’s negative appraisals and ostracism of other children who do not conform to gender stereotypes.

This research is supported by a Social Sciences and Humanities Research Council of Canada Insight Development Grant and a University of Toronto Connaught New Researcher Award awarded to Dr. VanderLaan.

Neuroimaging Studies of Gender Dysphoria and Transgenderism

We are currently conducting two neuroimaging projects using magnetic resonance imaging (MRI).

One project investigates structural brain development among Canadian adolescents who experience gender dysphoria (i.e., distress due to an incongruence between birth-assigned and experienced gender). In addition to investigating unique brain characteristics associated with gender dysphoria, this project longitudinally examines the neurological effects of sex hormone treatments often prescribed for gender dysphoria. These treatments are designed to help align physical secondary sex characteristics with the adolescent’s experienced gender identity, and this research will provide insight regarding possible effects of these treatments on brain maturation.

The second project compares brain structure in Thai heterosexual men and women, gay men, and sao praphet song (i.e., Thai “third” gender individuals who were assigned as male at birth, take on a feminine social role, and are sexually oriented toward men). By comparing brain structure across these groups, this research will help to disentangle sexual orientation from gender identity, thus allowing us to better discern which brain regions are related to sexual orientation and which are related to gender identity.

The Canadian project on gender dysphoria is supported by a Canadian Institutes of Health Research Operating Grant awarded to Dr. VanderLaan, Dr. Chakravarty (Co-PI, Douglas Mental Health Institute), and Co-Investigators at the Centre for Addiction and Mental Health and the University of Toronto as well as by the Centre for Addiction and Mental Health. The Thai project is supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant awarded to Dr. VanderLaan and by the University of Toronto Mississauga.

Psychological Well-Being and Gender Expression in Children

A number of clinical studies have indicated that cross-gender behaviour and identity in children is linked to increased risk of behavioural and emotional problems such as depression, anxiety, and suicidality. We are currently pursuing studies that investigate childhood gender expression and psychological well-being in community-based Canadian samples to assess whether this pattern of risk extends to non-clinical populations. To the extent that such risk is present in children from the community, we are also investigating contributing factors, including peer rejection and bullying experienced by children who display cross-gender behaviour and/or identity. Possible protective factors such as parental support are also being considered. This research will help clarify how childhood gender expression is related to mental health needs in the broader population, and will provide insight into strategies for ameliorating behavioural and emotional problems in these children.

This research is supported by a University of Toronto Mississauga Research and Scholarly Activity Fund Award awarded to Dr. VanderLaan.