Hormonal Factors Influencing Gender Identity
Biological factors play a huge role in shaping children's physical development. For instance, boys and girls are born with distinctive sexual organs, and become further differentiated when secondary sexual characteristics emerge upon puberty. Naturally occurring chemical messenger compounds in the body known as hormones are responsible for coordinating the appearance of these physical differences.
Some research suggests that the same sex hormones that enable sexual organ differentiation in utero and which later trigger puberty also pl an important role in shaping gender identity. Boys tend to have more androgens (male sex hormones) than girls. However, some boys and girls are born with a condition called congenital adrenal hyperplasia (CAH), which causes them to have significantly higher levels of androgens than their non-affected peers. Scientists have studied children with CAH in order to understand how their extra androgen levels affect behavior. Boys with excess androgens play and behave much like normal male peers. However, girls with high androgen levels tend to display more gender-stereotypic male traits and behaviors than do than their same-age hormonally-normal peers. In addition, girls with CAH are born with external genitalia that look like male genitalia. Though these girls appear to have penises, they are still female. Girls' true gender is determined genetically rather than anatomically. Females possess two "X" chromosomes, while males possesses a single "X" chromosome and a "Y" chromosome.
Even after girls with CAH have surgeries to make their genitalia look more characteristically female, they continue to show heightened masculine traits. For instance, they prefer to play with male peers; tend to choose traditionally masculine toys and activities (e.g., blocks, cars, models, sports) over more "feminine" toys and games; and are physically active and aggressive. In addition, girls with CAH tend to avoid having girl playmates; don't play games revolving around stereotypical feminine events such as playing at being a mother or bride; and tend to care less about their physical appearance than do girls of their age who do not have CAH. In other words, higher levels of male hormones strongly influence girls to behave as though they were boys.
Social and Environmental Factors Influencing Gender Identity
Other studies have shown that children's upbringing and social environments also impacts their developing gender identities. This work can be summarized by stating that children's interests, preferences, behaviors and overall self-concept are strongly influenced by parental and authority figure teachings regarding sexual stereotypes occurring in or before the early portion of middle childhood. Children who are taught that certain traits or activities are appropriate or inappropriate for them to engage because they are a girl or a boy do tend to internalize and be influenced by these teachings in later life. For instance, girls who are informed that boys are innately better at math than they are may report that they dislike math and disclaim their interest in that subject. They may go on to believe that they are not good at this academic subject, and to perform poorly on math tests and homework assignments.
Children learn vicariously, in part, through their observation and imitation of what they see their primary caregivers doing. They tend to imitate and internalize what they see and then repeat those patterns in their own lives as though they had come up with them independently. Children raised watching their parents adhering to strict gender-stereotyped roles are, in general, more likely to take on those roles themselves as adults than are peers whose parents provided less stereotyped, more androgynous models for behaving.
Homosexual, Bisexual and Trans-gendered Youth
Subject as they are to intense biological and social conditioning pushing them towards a particular conclusion, most boys develop a primarily masculine gender-identity, and most girls develop a primarily feminine gender-identity. Though their willingness to engage in cross-gender stereotyped behaviors may vary, such children are the same in that their experience is one of essential comfort and lack of anxiety with regard to their sexual and gender status. Their gender identity feels natural and normal to them. The things they want to do, socially and sexually, are consistent and congruent with what family and society want them to do. There is no sense that they have been strong-armed into becoming something they are not.
A minority of boys and girls do not experience this sense of comfort and congruence. These youth have a different experience of anxiety and incongruence due to their gender-identity being out of sync with social expectation because of their homosexual or trans-gender identity. Children who develop a homosexual sexual preference experience a physical-gender-consistent gender identity, meaning that they are boys who feel comfortable and normal being boys, or girls who feel comfortable and normal being girls. However, they find themselves sexually attracted to homosexual (same-sex) peers rather than the normal case of heterosexual (opposite-sex) attraction. Trans-gendered youth have developed a gender identity in opposition to their physical gender. They may be physically male but experience themselves as female, or physically female but experience themselves as male.