In endometriosis aberrant E2 production raises questions on ovarian differentiation. FSHR and INSL3 upregulation in eutopic/ectopic, and LHR in ectopic lesions are found. Ovarian GATA4/6 are upregulated in eutopic/ectopic lesions and induced by FSHR and LHR. FSHR and LHR induce steroidogenic enzymes and the ERK pathway in endometriotic cells. New pathophysiological mechanism of endometriosis with tools for diagnosis is shown.