A 25-year-old female states that she and her husband have been trying to have a baby for the last two years. The patients medical history included cyclical pelvic pain, dysmenorrhea, dyspareunia, and, not uncommonly, infeility. The physical exam reveals the following: diffuse abdominal or pelvic pain of variable location, nodular thickening and tenderness along the uterosacral ligaments, on the posterior surface of the uterus, and in the posterior cul-de-sac, scarring and narrowing of the posterior vaginal fornix, and adnexal enlargement and tenderness. What is your diagnosis?