NOS3 and endometriosis: No statistically significant differences were found in genotype distributions and allele frequencies between cases and controls across codominant, dominant, and recessive models. The protein’s localization and expression were similar in the endometrium of both groups./In this study, we found no difference in eNOS expression and no association between the eNOS Glu298Asp exon 7 polymorphism and endometriosis in South Indian women.