Gender identity disorders have traditionally been treated as psychiatric problems but researchers at Boston University School of Medicine say there is increasing evidence of a biological basis for the condition.
It's estimated that as many as 1 in 100 people have gender identity issues. Transgender persons identify with a gender that differs from the identity they were assigned at birth.
The researchers conducted a literature search and reviewed articles that showed positive biologic bases for gender identity. These included disorders of sexual development, such as penile agenesis, neuroanatomical differences, such as grey and white matter studies, and steroid hormone genetics, such as genes associated with sex hormone receptors.
They conclude that current data suggests a biological cause for transgender identity.
"This paper represents the first comprehensive review of the scientific evidence that gender identity is a biological phenomenon," said Joshua D. Safer, MD, FACP, in a review article in Endocrine Practice. "As such it provides one of the most convincing arguments to date for all medical providers to gain the transgender medicine skills necessary to provide good care for these individuals," he added.
Many physicians resist providing surgical and hormonal treatment to patients with gender issues, instead referring the patients for psychiatric care.
The findings of the review study may change physicians' perspective on transgender medicine and improve health care for these patients, Safer said.
According to the researchers the article does have some limitations due to the small numbers of individuals studied and therefore conclusions should be drawn with caution. Safer recommends that further research focus on specific biologic mechanisms for gender identity.