Adolescent Development

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Physical development

Adolescence is characterized by dramatic physical changes moving the individual from childhood into physical maturity. Early, prepubescent changes are noted with the appearance of secondary sexual characteristics.

Girls may begin to develop breast buds as early as 8 years old, with full breast development achieved anywhere from 12 to 18 years. Pubic hair growth (as well as armpit and leg hair) typically begins at about age 9 or 10 and reaches adult distribution patterns at about 13 to 14 years.

Menarche (the beginning of menstrual periods) typically occurs about 2 years after initial pubescent changes are noted. It may occur as early as 10 years, or as late as 15 years, with the average in the United States being about 12.5 years. A concurrent rapid growth in height occurs between the ages of about 9.5 and 14.5 years, peaking somewhere around 12 years.

Boys may begin to note scrotal/testicular enlargement as early as 9 years of age followed closely by lengthening of the penis. Adult size and shape of the genitals is typically reached by age 16 to 17 years. Pubic hair growth (as well as armpit, leg, chest, and facial hair) in males usually begins about age 12 years and reaches adult distribution patterns at about 15 to 16 years.

A concurrent rapid growth in height occurs between the ages of about 10.5 to 11 and 16 to 18, peaking somewhere around 14 years. Puberty is not marked with a sudden incident in males, as it is with the onset of menstruation in females. The appearance of regular nocturnal emissions "wet dreams", which may occur about every 2 weeks with the build-up of seminal fluid, marks the onset of puberty in males.

This typically occurs somewhere between the ages of 13 to 17 years, with the average at about 14.5 years. Voice changes in the male typically occur parallel to penile growth, the occurrence of nocturnal emissions and the peak of the height spurt.