Endometriosis: Endometriosis is a common disorder of the female reproductive organs and is the leading cause of chronic pelvic pain in women. Examples of causes of endometriosis include genetics, retrograde menstruation, coelomic metaplasia, surgical procedures, and abnormalities in the immune system. Treatments for endometriosis range from medications to surgery. In women who have endometriosis, tissue like the lining ...