1. Ovarian morphology: Transvaginal ultrasound will be performed in the follicular phase in controls and during amenorrhea in PCOS women. Ovarian volume will be calculated. Antral follicle number, defined as the total follicle number (2-9 mm in diameter) of both ovaries, will be determined by 1 investigator (D.A.D.). Polycystic ovaries will be defined by 12 or more follicles in each ovary measuring 2-9 mm in diameter, and/or increased ovarian volume (> 10 ml), with one such ovary sufficient to define PCO.