Among 53 polymorphic locus analysis, we found that the following variant alleles were significantly associated with decreased PCOS risk: The A>G allele distributions at rs9340799 in ESR1 (P = 0.000), the A>T at rs709154 (P = 0.013), and A>C at rs1151996 (P = 0.013) in PPARG. the A>C at rs2272046 in HMGA2 (P = 0.000), and the T>C at rs1801133 in MTHFR (P = 0.000, Table 3). The gene discussed is MTHFR; the disease is polycystic ovary syndrome.