CAH is a genetic steroidogenesis disorder. The most common form, 21OHD, leads to cortisol deficiency and, in turn, an excess of androgen, a hormone that promotes the development and maintenance of male sex characteristics. As a result of this androgen excess, prepubescent males and newborn, prepubescent, and grown females exhibit mature masculine characteristics. The symptoms and severity of 21OHD vary among individuals with the disease and in adults versus children. The reasons for these differences are not yet known. Current therapy for 21OHD consists of administration of glucocorticoids to replace cortisol and suppress excessive pituitary function. With more information about what genes or factors contribute to the severity of 21OHD, researchers may be able to better treat children and adults with the disease. This study will examine participants' DNA to determine what other genes may affect the severity of 21OHD and may make the disease milder in adults than in children.