Women with PCOS demonstrate normal or elevated levels of serum estradiol relative to controls (Kawwass et al., 2017; Laven et al., 2002), but they exhibit reduced ovarian aromatase activity with a corresponding decrease in the ovarian estrogen‐to‐testosterone ratio (Chen et al., 2015; Hunter & Sterrett, 2000; Jakimiuk et al., 1998; Kirilovas et al., 2006). This evidence concerns the gene CYP19A1 and polycystic ovary syndrome.