FSHR and endometriosis: Furthermore, a significantly decreased risk for endometriosis was also observed in women who had at least a mutant allele in FSHR at position 680 (genotype GG+GA, 680Ser/Ser+680Ser/Asn) and position 307 (genotype GG+GA, 307Ala/Ala+307Ala/Thr) (P = 0.01; OR = 0.66) (Table 4).