In contrast, the relative mRNA expression of ERα was significantly lower in the PCOS group (0.209 ± 0.119 vs. 1.019 ± 0.449, P = 0.004), while no significant difference in the mRNA expression of ERβ was observed between the two groups (0.839 ± 0.501 vs. 0.741 ± 0.691, P = 0.798). The gene discussed is ESR2; the disease is polycystic ovary syndrome.