Under pathological conditions such as polycystic ovary syndrome (PCOS), ovaries are significantly enlarged and individual theca cells produce excessive amounts of androgens due, at least in part, to increased expression of several genes involved in steroidogenesis, including STAR, CYP11A1, HSD3B2 and CYP17A1[2-4]. This evidence concerns the gene CYP17A1 and polycystic ovary syndrome.