Hormonal changes during puberty have been well described: rise of gonadotropins followed by the rise of gonadal secretions at ages 10 to 16 years. The most striking new data are in fact concerning events that occur before puberty, first during the first months of life, second at age 7 years. The first event consists of a rise of gonadal steroids, which gives a hormonal impring that might be important for the future of the child. The second event concerns the prepubertal maturation of the androgenic zone of the adrenal cortex and the increasing secretion with age of the adrenal androgens. The mechanism of onset of both events is poorly explained. What causes the rise of gonadal steroids during infancy is unknown. Which pituitary factor, in addition to ACTH, stimulates the corticoadrenal androgenic zone, and which mechanism regulates its secretion remain unknown.