Boys:
Stage One: Ages 9-12, no visible sexual development
Stage Two: Ages 9-15, height increases, muscle tissue develops
Stage Three: Ages 11-16, penis grows, menarche begins in girls
Stage Four: Ages 11-17, adult-looking genitals, ejaculation appears
Stage Five: Ages 14-18, full adult height and appearance
Girls:
Stage One: Ages 8-11, ovaries enlarge
Stage Two: Ages 8-14, breast development
Stage Three: Ages 9-15, menarche begins
Stage Four: Ages 10-16, ovulation may start
Stage Five: Ages 12-19, regular ovulation