Young people between the ages of 12 and 18, also known as adolescents, undergo a wide array of changes as they make the transition from childhood to adulthood. Many of those changes are physical and range from general increases in body size to the specific changes involved in the development of adult sexual characteristics.
Preadolescence
The physical development of both males and females actually begins in the years prior to adolescence, according to the U.S. National Library of Medicine's Medline Plus. For instance, your daughter may experience the first signs of breast development as early as age 8, while your son may experience the first signs of scrotum and testicle enlargement as early as age 9. For girls, the growth of pubic, leg and armpit hair starts by age 9 or 10, although boys will typically not experience hair growth until the onset of actual adolescence.
Female Puberty
Your daughter's sexual development will typically take place as a sequence of events, according to Kids Health. After breast and pubic hair development begin, she will experience an increase in the size of her vagina, uterus, clitoris and labia. She will typically experience the onset of menstruation, also called menarche, roughly two years after sexual development begins, Medline Plus reports. In some cases, menstruation may begin as early as age 10, while in others it may not begin until your daughter reaches age 15.
Male Puberty
After you son's scrotum and testicles start to enlarge, he will experience a lengthening of his penis and enlargement of his prostate gland and semen-carrying vesicles, according to the Merck Manuals Online Medical Library. Hair growth typically first occurs in the pubic region, then appears on his face and under his arms roughly two years later. Between the ages of 12 and 14, your son may begin ejaculating, although this development may occur as late as age 18. Early ejaculation occurs without fertility, the Merck Manuals report. Kids Health lists additional signs of male puberty that include a deepening voice and an enlargement of the larynx cartilage, or Adam's apple.
Female Growth
Your daughter will experience a growth spurt between the ages of 9 and 14, the Merck Manuals explain. The maximum rate of growth will occur roughly in the middle of this period, when she may grow as much as three and a half inches in one year. Menstruation typically occurs after this time of maximum growth, Kids Health notes. After menstruation, your daughter may grow another one to two inches and reach her adult height by roughly age 14 or 15.
Male Growth
Your son will experience a growth spurt between the ages of 12 and 17, the Merck Manuals note. At its maximum, his growth rate will reach roughly four inches in a one-year period. As a general rule, male children grow both taller and heavier than females. Once adult height is achieved, your son will continue to experience muscle growth and development, according to Kids Health.
