Occasionally, males and females feel that there is a mismatch between their gender and sexual identity. The most extreme case is transsexualism where people opt to change their sex surgically. This feeling is known as gender dysphoria.
A biological explanation of gender dysphoria is that it may be caused by abnormal prenatal exposure to androgens. Alternatively, they may just naturally produce an abnormal level of hormones during their development. For example, more testosterone could cause an XX female to have masculinised genitals and/or behaviour, as seen in people with Congenital Adrenal Hyperplasia.
Another biological explanation for gender dysphoria is that people may have defective genes which are responsible for regulating and controlling hormone production and gender development. For example, our genes carry androgen receptors with control and regulate the production of testosterone. As a result, it is possible that if there is a problem with these genes, then the person may experience gender dysphoria.
The third explanation is the brain sex theory. A region of the brain known as the BSTc (bed nucleus of the stria terminalis) is twice as large in men than in women and contains twice the number of neurons. The number of neurons in the BSTc of male to female transsexuals is similar to that of the females, suggesting that the size of the BSTc correlates with preferred sex, rather than the biological sex.
Hare took gene samples from male dysphorics and non dysphorics. He found that the number of androgen receptor sites correlated with the strength of the dysphoria. This provides strong evidence for the roles of genes and biology in the development of dysphoria.
However, Gladue researched hormone levels in dysphoric males and non dysphoric males. He found no significant difference between the two, challenging the role of…