CXCL12 and endometriosis: When these uteri were used in our endometriosis model, lesions still grew to sizes comparable to those of CXCL12fl/fl controls (0.762 ± 0.104 mm2, n = 35 lesions vs 0.547 ± 0.118 mm2, n = 12 lesions, respectively, P = NS) (Figure S3b) and exhibited comparable cycle‐matched proliferation (Figure S3c), suggesting that expression of CXCL12 by the endometriosis lesion is not essential for lesion development.