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milestonesPUBERTAL DEVELOPMENT IN NORTH AMERICAN BOYS AND GIRLS

AV E R A G E A G E AV E R A G E A G E G I R L S A T T A I N E D A G E R A N G E B OY S A T T A I N E D A G E R A N G E

Breasts begin to “bud.” 10 (8–13) Testes begin to enlarge. 11.5 (9.5–13.5)

Height spurt begins. 10 (8–13) Pubic hair appears. 12 (10–15)

Pubic hair appears. 10.5 (8–14) Penis begins to enlarge. 12 (10.5–14.5)

Peak of strength spurt. 11.6 (9.5–14) Height spurt begins. 12.5 (10.5–16)

Peak of height spurt. 11.7 (10–13.5) Spermarche (first ejaculation) 13 (12–16)

Menarche (first menstruation) 12.8 (10.5–15.5)occurs.

occurs. Peak of height spurt. 14 (12.5–15.5)

Adult stature reached; 13 (10–16) Facial and body hair begin to 14 (12.5–15.5)underarm hair appears. grow.

Breast growth completed. 14 (10–16) Voice begins to deepen. 14 (12.5–15.5)

Pubic hair growth completed. 14.5 (14–15) Penis growth completed. 14.5 (12.5–16)

Peak of strength spurt. 15.3 (13–17)

Adult stature reached. 15.5 (13.5–17.5)

Pubic hair growth completed. 15.5 (14–17)

Note: These milestones represent overall age trends. Individual differences exist in the precise age at which each milestone is attained.Sources: Malina & Bouchard, 1991; Tanner, 1990.

menarcheFirst menstruation.

spermarcheFirst ejaculation of seminal fluid.

II F O U N D A T I O N S O F D E V E L O P M E N T

S E X U A L M AT U R AT I O N I N G I R L S

Menarche (from the Greek word arche, meaning “beginning”) is the scientific name for firstmenstruation. Because most people view it as the major sign that puberty has arrived in girls,you may be surprised to learn that menarche actually occurs late in the sequence of pubertalevents. Female puberty usually begins with the budding of the breasts and the growth spurt.(For about 15 percent of girls, pubic hair is present before breast development.) Menarchetypically happens around 123⁄4 years for North American girls, 13 for Europeans. But the agerange is wide. Following menarche, pubic hair and breast development are completed, andunderarm hair appears. Most girls take about 3 to 4 years to complete this sequence, althoughthis, too, can vary greatly, from 11⁄2 to 5 years (Tanner, 1990; Wheeler, 1991).

All girls experience menarche after the peak of the height spurt, a sequence that is adaptive.Nature delays menstruation until the girl’s body is large enough for successful childbearing. As

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