The Growing Child: Adolescent (13 to 18 Years)

How much will my adolescent grow?

The teenage years are also called adolescence. During this time, parents will see the greatest amount of growth in height and weight in their child. Adolescence is a time for growth spurts and puberty changes. An adolescent may grow several inches in several months followed by a period of very slow growth, then have another growth spurt. Changes with puberty (sexual maturation) may occur gradually or several signs may become visible at the same time.

There is a great amount of variation in the rate of changes that may occur. Some teenagers may experience these signs of maturity sooner or later than others. The following indicates the average for adolescents 13 to 18 years old:

Growth increases:

Females (between 13 to 18 years)

Weight:68 to 110 pounds

Height:8.5 to 9.5 inches

Males: (between 13 to 18 years)

Weight: 76 to 118 pounds

Height: 10.5 to 20 inches

Puberty changes:


8 to 13 years of age


9.5 to 14 years of age

What changes will occur during puberty?

Sexual and other physical maturation that occurs during puberty is a result of hormonal changes. As a child nears puberty, a gland in the brain, called the pituitary gland, increases the secretion of a hormone called follicle-stimulating hormone (FSH). This hormone then causes additional effects. In girls, FSH activates the ovaries to start producing estrogen. In boys, FSH causes sperm to develop.

In boys, it is difficult to know exactly when puberty is coming. There are changes that occur, but they occur gradually and over a period of time, rather than as a single event. While each male adolescent is different, the following are average ages when puberty changes may occur:

  • Beginning of puberty: 9.5 to 14 years old

  • First pubertal change: enlargement of the testicles

  • Penis enlargement: begins approximately one year after the testicles begin enlarging

  • Appearance of pubic hair: 13.5 years old

  • Hair under the arms and on the face, voice change, and acne:15 years old

  • Nocturnal emissions (or "wet dreams"): 14 years old

Girls also experience puberty as a sequence of events, but their pubertal changes usually begin before boys of the same age. Each girl is different and may progress through these changes differently. The following are average ages when puberty changes may occur:

  • Beginning of puberty:8 to 13 years

  • First pubertal change: breast development

  • Pubic hair development: shortly after breast development

  • Hair under the arms: 12 years old

  • Menstrual periods: 10 to 16.5 years old

There are specific stages of development that both boys and girls go through when developing secondary sexual characteristics (the physical characteristics of males and females that are not involved in reproduction such as voice changes, body shape, pubic hair distribution, and facial hair). The following is a brief overview of the changes that occur:

  • In boys, the initial puberty change is the enlargement of the scrotum and testes. At this point, the penis does not enlarge. Then, as the testes and scrotum continue to enlarge, the penis gets longer. Next, the penis will continue to grow in both size and length.

  • In girls, the initial puberty change is the development of breast buds, in which the breast and nipple elevate. The areola (dark area of skin that surrounds the nipple of the breast) increases in size at this time. The breasts then continue to enlarge. Eventually, the nipples and the areolas will elevate again, forming another projection on the breasts. At the adult state, only the nipple remains erect.

  • Pubic hair development is similar for both girls and boys. The initial growth of hair produces long, soft hair that is only in a small area around the genitals. This hair then becomes darker and coarser as it continues to spread. The pubic hair eventually looks like adult hair, but in a smaller area. It may spread to the thighs and, sometimes, up the stomach.

Did You Know?

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Only 32 percent of U.S. children attend physical education classes daily. Parental encouragement can help them be more active outside of school.