Testosterone and Breast Enlargement: New Support of "Androgens in Human Evolution," www.anthropogeny.com/evolution.html I just found the following citation which may add support to my contention that enlarged breasts in human females may come from the extra testosterone that human females produce. Testosterone levels are higher in human males and females than chimpanzee males and females respectively. Int J Impot Res. 2004 Jan;16(1):95-7. Treatment of testosterone-induced gynecomastia with the aromatase inhibitor, anastrozole. Rhoden EL, Morgentaler A. 1Division of Urology, Beth Israel Deaconess Medical Center, Men's Health Boston, Harvard Medical School, Massachusetts, USA. Gynecomastia is an unusual side effect associated with testosterone replacement therapy (TRT) that has been traditionally treated with surgery, radiation, or discontinuation of testosterone supplementation. We report here our experience with two cases of gynecomastia in men undergoing TRT who were successfully treated with the aromatase inhibitor anastrozole.