Our awareness of sex generally begins during our adolescent years. Adolescence is the time when our bodies change from child form to adult form. The exact time when these changes begin, which is called puberty, varies from person to person.
Boys to Men
For boys, the changes begin to be noticeable between the ages of 11 and 13, though it is normal for a boy to begin as early as nine or as late as 16. Puberty actually begins a year or two earlier, but the changes are so subtle that most boys do not notice them. About one year after noticeable signs of puberty, a boy enters a rapid growth phase. On average, a boy will increase in height about two inches per month during his growth spurt, which then tapers off, though he continues to grow. Full adult height is usually gained by the age of 18, though many men will continue to add a half to one inch in height in their early twenties.
The whole period of adolescence covers 8 to 10 years for most boys. Those who start early tend to take longer to develop. Those who start late tend to take less time to develop. Even after outward changes have stopped, there are still changes occurring inside. Recent research shows the typical male’s brain does not finish “rewiring” itself into an adult pattern until a man reaches his mid-twenties. One of the last areas to develop is the portion of the brain that governs risky behavior. This is why your auto insurance premiums often do not drop until you reach 25 years of age.
Since growth consumes a great deal of energy, the typical teenage boy eats about 5,000 calories daily while the typical adult male only needs 3,000 calories daily. Since many men do not marry until their early twenties, they often associate weight gain around the middle with their wives’ good cooking. In reality, they have made a habit of eating large meals, and, now that they are no longer growing, the excess calories are stored as fat in the belly.
Girls to Women
Girls show puberty changes earlier than boys. These changes are usually noticed between the ages of 9 and 11, though it is normal for a girl to begin as early as 8 or as late as 14. Most girls begin puberty with a rapid change in height. They typically reach their full adult height between the ages of 15 and 16.
Even after a young woman reaches her full height, her body continues to develop for an additional two years. During this time, the breasts enlarge and the hips widen. Overall, the growth period for a typical girl lasts about five years. Yet, even after the outward signs of growth have stopped, young women continue to develop internally. The brain continues to “rewire” itself through your late teens. Your reproductive system continues to mature as well. Even though a girl may begin menstruation between the ages of 9 and 16 (13 being the most typical age to begin), her body is not fully prepared to handle the growth of a child in her womb. Girls who become pregnant before the age of 16 run a 40 times greater risk of dying and are more likely to miscarry.
Because women reach full maturity faster than men, it is typical for young teenage girls to tower over boys of the same age. This is also why they view the thinking of boys their own age as being so immature—it is, but they should not be deceived into thinking their own thinking is fully matured simply because they have progressed farther than boys of their own age.