The production of sex hormones results in the growth of breasts in girls, a broadening of the hips, and the start of menstruation. In case of boys, the body becomes more muscular, testes and penis increase in size, the production of semen starts, and the night ejaculations begin. This is the time for first loves and understanding sexual orientation. A lot of activity goes on in the brain too. New nerve paths arise, and old ones disappear.
