Additional Study Information: Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women ofreproductive age, affecting about 7% of this population when using the strictest diagnostic criteria and frequently presents in adolescence and young adulthood. Diagnostic features of PCOS includehyperandrogenism and ovulatory dysfunction. Additionally, both obese and nonobese individuals with PCOS frequently develop features of the metabolic syndrome, including insulin resistance anddyslipidemia. In fact, insulin resistance affects up to 70% of those affected with PCOS and has beenincreasingly implicated to underlie the hormonal and metabolic derangements as well as the clinicalabnormalities of PCOS. Early identification and treatment of the metabolic and body compositionabnormalities associated with PCOS will potentially prevent lifelong morbidity associated with thisdisorder, which is significant in light of the large numbers of young individuals with PCOS and theirincreased risk of development of IR, NAFLD and dyslipidemia. We are recruiting healthy adolescent girls and young women with and without PCOS between the ages of 13 and 25 years to participate in a study to help better define the metabolic and body composition abnormalities associated with PCOS.