CYP19A1 and polycystic ovary syndrome: As a result, the presence of the “G” allele made them more prone to developing PCOS, while carriers of the “A” allele were less common in PCOS than in controls, implying that the presence of the “A” allele could be linked with the aromatase activity responsible for normal androgen levels, which can protect the ovaries from developing PCOS.