Normal puberty begins between eight and 14 years of age in girls and between nine and 14 years of age in boys. Pubic hair distribution is used to stage puberty, along with breast size and contour in girls and testicular volume in boys. Some children experience constitutional sexual precocity, but precocity is likely to be pathologic if it occurs in very young children, if there is contrasexual development or if the sequence of normal pubertal milestones is disrupted. Delayed puberty may be constitutional, but pathologic causes should be considered. The etiology of a pubertal disorder can often be determined with the use of a focused medical history, a directed physical examination and appropriate diagnostic tests. Treatment for disorders of puberty is determined by the underlying cause.