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 dominating all subordinate material instincts, becomes similar to God. This similarity must be goal of all human undertaking. Gregory of Nazianzus (330-390) contemplated on the origin of the human body. Man was created by God with body and soul, a visible and invisible part, like the angels. He was created to praise God like they did. The body was given to man, so he may suffer and eventually die, and thus not consider himself to be God. The material essence of the body separates us from God, like a cloud, or, as Gregory stated, like the cloud between the Egyptians