These data gaps include: (1) a paucity of evidence regarding LH pulse frequency and amplitude in women with endometriosis, (2) incomplete knowledge regarding the mechanisms by which ovarian alterations in endometriosis, especially low testosterone and low AMH, influence endometrial function, particularly the establishment, growth and inflammation of endometrial tissue at ectopic sites, and (3) lack of clarity on how variation in ovarian or serum testosterone levels influences eutopic and ectopic endometrial tissues. This evidence concerns the gene PLOD1 and endometriosis.