Development of the human body used to approximately judge a child's age based on physical development. Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs. Physical growth—height and weight—accelerates in the first half of puberty and is completed when an adult
Catholic theology of the body God in his image. This is considered important even today, as the existence of a soul is the basis for much Church teachings on the human body, in areas such as abortion. Ambrose of Milan and Augustine of Hippo applied these views in their teachings on the human body, virginity and celibacy. Thomas Aquinas developed a systematic view, which dominated Church teachings and ecumenical councils including Vatican II. All recent popes contributed from different angles to the theology of the body. Current issues include the dignity of the body in light of its divine origin and destination, its eventual resurrection;