Girls generally precede boys by approximately two years. Girls can begin to show signs of development as early as age nine, where boys usually begin to show signs of development at age eleven. It is common to see physical changes in both sexes by fifth grade. When recalling their first conscious sexual thoughts, most students report these occurred at about age nine years. Sexual development is a major part of adolescence.
Sexuality flows from the onset of physical changes.
It is an inevitable, universal occurrence. Specifically, for girls, the changes include menarche and breast development. As boys and girls progress through the changes of adolescence, they are acutely aware of their peer group. Adolescents are consistently evaluating themselves and comparing themselves to their classmates. The concept of body image becomes very important to both boys and girls.