Aromatase inhibitors appear to have a promising effect on pain associated with endometriosis, however, their use is associated with the side effects of creating a dramatically hypoestrogenic environment, such as bone density loss.Selective estrogen receptors modulatorsTheoretically, drugs which block the estrogen receptors should interfere with endometriosis development and progression. The gene discussed is CYP19A1; the disease is endometriosis.