Physical Development, Ages 11 to 14 Years

Adolescence is a time of rapid growth in height and weight and of physical changes throughout the body. Most of these changes happen near the time of puberty. Puberty usually starts between the ages of 8 and 13 in girls and between the ages of 9 and 14 in boys.

During female puberty:

• Breast buds (slight raising and enlargement of the nipple area) are one of the first signs of puberty. Pubic hair usually starts growing around the same time.
• Body fat increases, especially around the hips and thighs, breasts, and upper body.
• Early puberty is usually a time of rapid growth. Then growth slows down with the first menstrual period. Teens reach their approximate adult height around 16 years of age.
• Periods usually start sometime between ages 11 and 14. They can start as early as age 9 or up to age 15.

During male puberty:

• The first sign of puberty is that the testicles get larger. This is followed by the growth of pubic hair and by penis lengthening.
• Hair growth usually starts on the upper lip. It gradually reaches the cheeks and then the chin area.
• Body fat and muscle mass increase during this time.
• The growth spurt occurs after other signs of puberty have developed. During early adolescence, growth in teens going through male puberty tends to lag. But over time their growth typically surpasses the growth of teens going through female puberty. This is because after male growth starts, it happens faster and for a longer period of time. Approximate adult height is reached at about 18 years of age.

Growth in body parts may occur out of sync with each other. For example, the nose, arms, and legs may grow faster than the rest of the body. Other physical development during puberty usually includes:

• Bone growth. This increases your child's height.
• An increase in skull bone thickness. The forehead becomes more prominent, and the jaw grows forward.
• Weight gain. A child's weight almost doubles during adolescence.
• An increase in the size of organs. The heart doubles in weight, and lung size increases.

The surging hormones related to puberty often stimulate the sex drive. It's normal to masturbate in private. Hormones may also trigger episodes of difficult behavior, such as challenging parents and other authority figures.