Studies under this protocol will be performed in normally cycling women and in women with PCOS from 18 to 35 years old. Criteria for PCOS will be (a) clinical and/or biochemical evidence of hyperandrogenism, (b) oligomenorrhea, and (b) the absence of clinical or biochemical evidence of other potential causes of hyperandrogenism and/or oligomenorrhea. After informed consent is obtained, all potential subjects will undergo a screening history and physical exam. Subjects will need to fast for a minimum of 8 hours prior to screening blood draw. After informed consent is obtained, blood tests (~ 16 cc) will be drawn at 0800-0900 h as follows: LH, FSH, progesterone (P), estradiol (E2), total testosterone, SHBG, 17-OHP, androstenedione, DHEA-S, beta-hCG, TSH, prolactin, CBC, chemistry and liver panels, hemoglobin A1c, fasting insulin, and fasting glucose. Additionally, BOD POD® will be used to measure total fat mass, fat free mass, and percent body fat. Waist and hip circumference will be measured.