Gender Identity Development

Biological Influences on Gender

Within the womb, a fetus has undifferentiated sex organs, and this undifferentiated tissue has the potential to form a penis and testes, a vagina and ovaries, and ambiguous or blended sex organs. If there is an underlying genetic condition, variations in sex hormone (testosterone or estrogen), or differences in sex development within the first 20 weeks of gestation, intersexed sex organs may develop. Researchers have hypothesized that sex hormone variations that occur later in gestation may directly influence gender identity later in life. The so-called gendered brain that once described significant neurological differences between males and females has more recently been understood as a function of variance of sex hormones in the womb, rather than a difference influenced solely by genes. Researchers have also discovered that these brain variations occur on a spectrum, not a binary male–female system. Recent research has found that several of these gendered neurological variations are similar to the gender of youth’s identity, not to their sex organs. Although more research is needed in this area, it is a promising area of study to help understand gender identity development in general, as well as transgender identity development specifically. This research does support the idea, however, that gender identity may also be directly influenced by biological causes.

How Gender Identity Develops

Gender identity development is a complex process that occurs across the life span. Gender [Page 623]identity is distinct from sex assigned at birth and gender expression, and both cisgender and transgender individuals experience gender identity development. Gender-expansive and transgender individuals may have different identity development experiences depending on their level of alignment with cultural gender expectations, but identity and expression remain separate constructs.

Prior to the development of models of transgender identity development, scholars have noted a general trajectory of gender identity development in children and adolescents. Children begin to demonstrate the influence of biological and sociocultural factors on gender identity around the age of 2 or 3 years, although prior to that age infants and toddlers can identify caregivers through gender presentation and voice recognition. Toddlers often demonstrate awareness of gender stereotypes with regard to toys and clothing choices and, depending on the rigidity of caregiver gender roles and expectations, may begin to chastise or question encounters with gender fluidity. For example, a child who was assigned male at birth may hear admonishment when playing with a toy or favoring a color that the society has designated as belonging to a feminine gender (e.g., “Boys do not play with ‘girl’ toys”). Children at this age more often associate with others whose gender matches their own gender identity.

...