It means their bodies are turning into wonderful adult bodies that can enjoy sex and reproduce if they choose to. Yes, she said, but sometimes it seems adults lose sight of that. This is a very normal stage of development. Puberty is the biological term for reproductive maturation, when the body changes physically from being a child to one that can produce a child. In girls, among other changes, breasts develop as does the vagina and uterus.
Pubic hair grows.
Eggs in the ovaries start to mature each month. Menstruation, also called a period, begins. In boys, among other changes, the voice deepens, the testicles and penis get bigger and the testicles begin to make semen and sperm. Ejaculation can be achieved. Pubic hair grows, as do whiskers.