Gender Dysphoria and Transgender Identity Is Associated with Physiological and Psychological Masculinization: a Theoretical Integration of Findings, Supported by Systematic Reviews

Abstract

Introduction Gender dysphoria (GD) is associated with several psychiatric conditions, but the causal links are not known. We note that some of these conditions are associated with physiological masculinisation. Methods Here, we explore this association through a series of systematic reviews, using Google Scholar, on original studies that test the relationship between GD and at least one correlate of androgens, namely autism spectrum disorder, left-handedness, 2D:4D ratio, being male and male heterosexuality. Results Individuals with GD tend to exhibit scores that reflect heightened levels of androgens and masculinity compared with non-GD individuals. We further show that these same androgen indices are also associated with other identity disorders (or dysphoriae). Conclusions Autism is associated with masculinisation, and we argue that GD may reflect autism spectrum disorder traits that indirectly lead to anxiety and to one questioning one's sense of self. We note that this is consistent with Blanchard's transsexualism typology, which successfully integrates a wide range of empirical findings.

Biologizing Gender: The canalized reproductive axis of gender, not sex.

“…Nevertheless, this research highlights the probability of upstream biological causes for diversity. A likely candidate appears in the etiology of genetic and environmental influences (Castellanos-Cruz, Bao, & Swaab, 2017;Dutton & Madison, 2021). We predict that differential gene expression under the influence of epigenetic processes is a likely causal component (Author 1 & Author 2, b, in preparation); however, that ontology is beyond the remit of this current paper.…”

Biologizing Gender: The canalized reproductive axis of gender, not sex.

“…We did not seek a biological origin for trans identification, but this research highlights the probability of upstream biological causes for diversity. A likely candidate appears in the etiology of genetic and environmental influences (Dutton & Madison, 2021). We predict that differential gene expression under the influence of epigenetic processes is likely a causal component (Author 1 & Author 2, b, in preparation); however, that ontology is beyond the remit of this current paper.…”

The Biological Origins of Gender, not Sex: A Review of Psychobiological Evidence - Evolution and the Reproductive Axis

“…For brevity, this study did not explore a biological basis for trans identification, but it highlights a possible link between fetal environment, its genome, and epigenetic effects on temporally displaced neuronal and somatic development. Since the fetus is anatomically organized and produces sex hormones before brain activation (Bao & Swaab, 2011;Savic et al, 2010), it is likely that upstream biological factors contribute to gender diversity (Castellanos-Cruz, Bao, & Swaab, 2017;Dutton & Madison, 2021). A likely candidate for this etiology starts with epigenetic disruption to the fetal environment due to maternal exposure to internal and external factors like stress or toxins.…”