Why do you think these perceptions are so different between girls and boys?

What you have discovered from the readings and what research tells us is that the psychological effects of puberty are directly related to discrepancies between what adolescents think should happen and what actually does. Those whose development occurs outside of their expectations experience more negative outcomes and feelings. Research confirms the following:

a) Girls who are early developers experience lower levels of self esteem and have more negative body images. They are more likely to get in trouble at school and home, experience depression, and be involved in delinquent behaviors. They also tend to think of themselves as fat - this could be because girls must have at least 17% body fat to enter puberty and at least 22% body fat to maintain regular monthly cycles so their body fat does tend to be a little higher than girls who have not yet entered menarche.

b) Boys on the other hand that experience early development tend to have higher self esteem, do better in school and have more friends.