: Impairments in social relatedness and communication, repetitive behaviors, abnormal movement patterns, and sensory dysfunction characterize autism spectrum disorders (ASDs). Seventy consecutive patients with an ASD diagnosis (DSM-IV criteria, >/= 6 years-old) who presented to the Genetic Centers of America for outpatient genetic/developmental evaluations from 2005-2007 were examined. Patients were evaluated using CLIA-approved Laboratory Cooperation of America (LabCorp) testing for: serum testosterone, serum free testosterone, % free testosterone, serum/plasma dehydroepiandrosterone (DHEA), androstendione, and follicle-stimulating hormone (FSH). Morning blood samples collected following an overnight fast, compared to the pertinent reference means, showed significantly increased relative mean levels for: serum testosterone (158%), serum free testosterone (214%), percent free testosterone (121%), DHEA (192%), and androstenedione (173%). By contrast, compared to the pertinent reference mean, the relative mean level of FSH (51%) was significantly decreased. Additionally, at least one of the androgen attributes examined exceeded its recognized laboratory age- and sex-specific reference range in 81.4% (57 of 70) of the patients examined. With respect to their age- and sex-specific reference ranges, females had significantly higher overall mean relative testosterone and relative free testosterone levels than males. Increased androgens in patients diagnosed with ASDs may involve cyclical interactions between the androgen and the transsulfuration pathways, particularly following mercury exposure. A review of therapies that have significantly improved clinical outcomes in ASD patients indicates they share commonality in helping lower androgens. Thus, androgens should be routinely clinically measured in patients with an ASD diagnosis and appropriate androgen-lowering therapies considered for those who have significantly elevated levels.