Autism is a behavior disorder with a neural developmental origin. It is defined by its behavioral properties in the editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM). In the latest edition of the DSM, the DSM-IV-TR, autism is described by impaired functioning on three behavior domains: qualitative impairments in social interaction, qualitative impairments in communication, and the occurrence of stereotyped behaviors or restricted interests (1)

Autism affects males more than females; giving rise to the idea that the influence of steroid hormones on early fetal brain development may be one important early biological risk factor (2). The differences in circulating levels of gonadal hormones during fetal and infant development are responsible for most sexual dimorphism in adults. For normal male development to occur, sex hormones like testosterone act through estrogen receptors, which in turn also activate other genes and proteins.(3, 4). Estrogen directly influences brain function through estrogen receptors located on neurons in multiple areas of the brain (5).