In regularly menstruating women without endometriosis or PCOS, serum testosterone levels positively predict number of follicles and oocytes retrieved (Sun et al., 2014; Xiao et al., 2016), and women with higher serum testosterone require less FSH and a shorter duration of ovarian stimulation (Frattarelli & Peterson, 2004). This evidence concerns the gene BRD2 and polycystic ovary syndrome.