Penile erection is the result of a complex interaction of psychological, neural, vascular and endocrine factors, and is usually, though not exclusively, associated with sexual arousal. Puberty is the process of physical changes by which a child's body becomes an adult body capable of reproduction. Puberty is initiated by hormone signals from the brain to the gonads the ovaries and testes. The period during which adolescents reach sexual maturity and become capable of reproduction. Puberty is a painting created by Edvard Munch.