In 2010, the GWA study by Adachi et al validated an important association between endometriosis and A > G (rs13394619) polymorphism in the GREB1 gene of the 2p25.1 chromosome (OR = 1.35; 95%CI= 1.06–1.18; p = 3.8 × 10−5).16 In 2012, this association was also found (OR = 1.12; 95%CI =1.06–1.18; p = 2.1 × 10−5) in the meta-analysis that comprehended Japanese and European populations.10 When searching to replicate the results, a study in a Belgian population found association between rs13394619 and endometriosis at any stage, classified in accordance with the American Fertility Society. This evidence concerns the gene GREB1 and endometriosis.