It is rare and affects about 1 child in every 10,000 in the United States. The same hormone changes that cause puberty also cause precocious puberty. Premature stimulation of the endocrine system releases hormones from the pituitary gland. These hormones stimulate the testes to make sex hormones. The sex hormones, including testosterone, cause sexual maturation in boys.
Sex hormones accelerate growth as well as the skeletal process that ends growth.
Boys who start puberty prematurely are tall for their age, but growth stops earlier for them. Their full height potential as adults is never achieved. They often grow no taller than 5 feet 2 inches. Behavior changes occur during premature puberty. Some boys become more aggressive than their peers and develop a sex drive.