The subsequent subgroup analysis showed that the ER-β rs4986938 polymorphism was also significantly associated with an increased risk of endometriosis-associated infertility (dominant model, OR = 1.83, 95% CI = 1.26–2.67; recessive model, OR = 0.96, 95% CI = 0.34–2.72; AA vs. GG, OR = 1.23, 95% CI = 0.43–3.49; GA vs. GG, OR = 2.08, 95% CI = 1.59–2.71; A vs. G, OR = 1.72, 95% CI = 1.37–2.17; Figure 3). This evidence concerns the gene ESR2 and endometriosis.