puberty /p(y)o̅o̅″bərtē/ [L, pubertas, age of maturity] , the period of life at which the ability to reproduce begins. It is a stage of development when genitalia reach maturity and secondary sex characteristics appear. The onset normally occurs in females between 9 and 13 years of age with the development of breasts and menarche. In males, puberty usually occurs between 12 and 14 years of age and is characterized by the ejaculation of sperm.
