Physical Growth and Sexual Maturation of Adolescents

For height and weight charts for children 2 years of age and older, see growth charts from the Centers for Disease Control and Prevention (CDC).

There is a growth spurt during adolescence. The growth spurt in boys occurs during mid-adolescence between the ages of about 12 years and 16 years (most commonly about age 13½) and usually begins a year after the testes start enlarging. Boys grow about 4 inches (about 10 centimeters) during their year of maximum growth. The growth spurt in girls occurs in early adolescence between the ages of about 9½ years and 13½ years (most commonly about age 11½). Girls grow about 3½ inches (about 9 centimeters) during their year of maximum growth. In general, boys weigh more and are taller than girls.

If the timing of growth is not typical, particularly in a boy whose physical development is delayed (see Delayed Puberty Delayed Puberty Delayed puberty is defined as absence of the start of sexual maturation at the expected time. Most often, children simply develop later than their peers but ultimately develop normally. Sometimes... read more ) or a girl whose development occurs early (see Early Puberty Early Puberty Early (precocious) puberty is sexual maturation that begins before the average age. The cause of early puberty is often unknown, but it may be caused by structural abnormalities or tumors in... read more ), emotional stress is possible. Most children who grow slowly eventually attain normal height (see Constitutional Delay of Puberty Constitutional Delay of Puberty Hypogonadism is decreased production of testosterone, sperm, or both in males. Hypogonadism occurs when there is a problem in the testes or a problem in the pituitary gland or the hypothalamus... read more ). However, adolescents whose growth is delayed or abnormal (see Growth Hormone Deficiency in Children Growth Hormone Deficiency in Children ) should be evaluated by doctors to rule out diseases and other physical causes and be given reassurance.

Sexual maturation or puberty begins at different ages depending on genetic and environmental factors. Sexual maturity begins earlier today than a century ago, probably because of improvements in nutrition, general health, and living conditions. For example, the average age that girls begin menstruating has decreased by about 3 years over the past 100 years. However, whenever sexual maturation begins, it typically occurs in the same order.

In boys, sexual changes begin with enlargement of the scrotum and testes, typically followed by lengthening of the penis (see Puberty in Boys Puberty in Boys Puberty is the stage during which people reach full reproductive ability and develop the adult features of their sex. In boys, puberty usually occurs between the ages of 10 and 14 years. However... read more ). Next, pubic hair appears. Armpit and facial hair appears about 2 years after pubic hair. The growth spurt usually begins a year after the testes start enlarging. Boys in the United States typically have their first ejaculation between 12½ years and 14 years of age, about 1 year after penis growth accelerates. Young adolescent boys often have slight enlargement of the breasts (gynecomastia Breast enlargement in men Breast disorders occur infrequently in men. Breast disorders include Breast enlargement Breast cancer Breast enlargement in males is called either gynecomastia or pseudogynecomastia. Gynecomastia... read more ) that usually resolves within several years.

In girls, breast budding is the first sign of sexual maturation, followed closely by the start of the growth spurt (see Puberty in Girls Puberty in Girls Puberty is a sequence of events in which physical changes occur, resulting in adult physical characteristics and capacity to reproduce. These physical changes are regulated by changes in the... read more ). Shortly after that, pubic and armpit hair appears. Menstruation typically begins about 2 years after breast development starts and when growth in height slows after reaching its peak velocity. In the United States, most girls start their period at 12 or 13 years of age, but there is a wide range.

In both boys and girls, pubic and/or axillary hair may appear first. This appearance may be a normal variation but should be discussed with a doctor.

If sexual maturation begins too early (see Early Puberty Early Puberty Early (precocious) puberty is sexual maturation that begins before the average age. The cause of early puberty is often unknown, but it may be caused by structural abnormalities or tumors in... read more ) or is very delayed (see Delayed Puberty Delayed Puberty Delayed puberty is defined as absence of the start of sexual maturation at the expected time. Most often, children simply develop later than their peers but ultimately develop normally. Sometimes... read more ), doctors typically evaluate children for possible hormonal disorders.

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