Sexual Development in Adolescents

Most sexual development occurs in late childhood and adolescence. This period of rapid growth and development is called puberty. Puberty involves physical growth and sexual maturation, as well as psychological and social development.

Puberty usually begins between the ages of eight and 12 in girls and between the ages of 10 and 14 in boys. In some cases, puberty does not occur within the normal age range. This condition is called late puberty or delayed puberty.

Adolescents who experience delayed puberty should be evaluated by a health care specialist (e.g., endocrinologist) to rule out genetic disorders, such as Klinefelter syndrome (condition caused by an extra X chromosome in males) and Turner syndrome (condition caused by an incomplete or missing X chromosome in females), and other medical conditions (e.g., disorders of the thyroid or pituitary gland, diabetes, kidney disease).

Puberty occurs as a result of increased hormone levels triggered by an area of the brain called the hypothalamic-pituitary-gonadal axis. At the onset of puberty, the hypothalamus begins secreting gonadotropin-releasing hormone (GnRH) to the pituitary gland. The pituitary gland then begins secreting leutenizing hormone (LH), which stimulates special cells in the testes and ovaries to produce sex hormones called testosterone and estrogen. The increase in these hormones results in maturity associated with adulthood.

Signs of puberty in girls include the following:

  • Appearance of underarm and pubic hair
  • Breast development
  • Growth spurt (period of rapid growth; girls usually reach their adult height by about 16 years of age)
  • Menstruation (menstrual periods)
  • Increase in subcutaneous (under the skin) fat in the pelvis, breasts, and upper back

Signs of puberty in boys include the following:

  • Appearance of underarm, chest, facial, and pubic hair
  • Deepening of the voice
  • Ejaculation (reflex in which semen is ejected from the penis; usually follows an erection and may happen during sleep)
  • Growth spurt (period of rapid growth; boys usually reach their adult height by about 18 years of age)
  • Gynecomastia (condition in which a hard nodule forms under each nipple; usually disappears within 2 years)
  • Growth of the penis and testes (testicles)
  • Increase in muscle mass

In addition to physical signs of sexual development, puberty also involves psychological (emotional) and social development, in which the adolescent begins to establish his or her independence and own identity. During adolescence, teens begin to evaluate their personal strengths and weaknesses, create long-term goals, and make decisions about their future. Before this age, many kids have more unrealistic expectations about their future (e.g., "I'm going to be a professional athlete," "I'm going to marry a movie star."). They also begin to establish their sexuality.

In early adolescence, both boys and girls often struggle with body image and self-esteem. They may wonder if they are developing normally and may show an interest in members of the opposite sex. In fact, many young teens develop strong friendships with members of the opposite sex, in addition to friendships with members of same sex, which become increasingly important during this time.

During the middle teen years, adolescents often become more comfortable with their bodies and with their sexuality. Many teens begin dating between the ages of 14 and 16. At this age, adolescents usually are self-centered and relationships tend to be one-sided.

Social relationships develop substantially during late adolescence (i.e., after the age of 17). In this age group, dating often becomes more serious and intimate relationships, including sexual relationships, are much more common. Homosexual experimentation, which may or may not indicate homosexuality, as well as sexual promiscuity (with members of the opposite gender or members of the same sex) also are relatively common during this stage of sexual development.

Parents and caregivers should stress the importance of safer sex before adolescents become sexually active. Open communication about sexuality is an important part of healthy sexual development.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 26 Dec 2008

Last Modified: 13 Oct 2011