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
Theology of the Body of love... [or] communion of persons"" but rather is a mere bodily union. On the other hand, the licitness of natural family planning (NFP) methods is held to be evident from the structure of the human body, which has natural periods of fertility and infertility. The morality of these methods was literally designed into the body, and use of them, unlike use of artificial contraception, can actually improve the dialog between couples which is expressed through the language of the body. Throughout these speeches the main emphasis is on the intrinsic "goodness" of the marital act. The power of love