In a prospective case control study, Baskol and colleagues [158] reported that serum xanthine oxidase (XO) (a generator of ROS) activities were higher in women with PCOS than in control women while and antioxidant status is decreased as ascertained by decreased lipid antioxidant paraoxonase 1 (PON1) activity [158]. This evidence concerns the gene XDH and polycystic ovary syndrome.