Diseases & Conditions


Sexual Maturation (Delayed)

Delayed sexual maturation is a delay in the onset of puberty and the development of the sexual organs.

The onset of sexual maturation (puberty) takes place when one part of the brain, the hypothalamus, sends a chemical signal to another part of the brain, the pituitary gland. This signal tells the pituitary gland to begin releasing hormones called gonadotropins, which stimulate the growth of the sex organs (the testicles in boys and the ovaries in girls). The growing organs secrete sex hormones, such as testosterone Some Trade Names DELATESTRYL DEPOTESTOSTERONE (in boys) and estrogen (in girls). These hormones cause the development of sexual characteristics, including pubic and axillary hair in both sexes, facial hair and muscle mass in boys, and breast growth in girls, and of sexual desire (libido).

Some adolescents do not start their sexual development at the usual age. A delay may be perfectly normal, and in some families sexual maturation tends to occur later. In such adolescents, the growth rate before puberty is usually normal, and they otherwise appear healthy. Although the growth spurt and sexual maturation are delayed, they eventually proceed normally.

Various disorders, such as diabetes mellitus, inflammatory bowel disease, kidney disease, cystic fibrosis, and anemia, can delay or prevent sexual development. Development may be delayed in adolescents receiving radiation therapy or cancer chemotherapy. Adolescents, particularly girls, who become very thin because of excessive exercise or dieting often have delayed sexual maturation, including an absence of menstruation.

There are many uncommon causes of delayed sexual maturation. Chromosomal abnormalities (such as Turner syndrome in girls (see Chromosomal and Genetic Abnormalities: Turner's Syndrome )) and Klinefelter syndrome in boys (see Chromosomal and Genetic Abnormalities: Klinefelter's Syndrome ) and other genetic disorders can affect production of hormones. A tumor that damages the pituitary gland or the hypothalamus can lower the levels of gonadotropins or stop production of the hormones altogether. A mumps infection can damage the testicles and prevent puberty.

Symptoms and Diagnosis

In boys, the symptoms of delayed sexual maturation are lack of testicular enlargement by age 13½, lack of pubic hair by age 15, or a time lapse of more than 5 years from the start to the completion of genital enlargement. In girls, the symptoms are lack of breast development by age 13, more than 5 years from the beginning of breast growth to the first menstrual period, lack of pubic hair by age 14, or failure to menstruate by age 16. A short height (short stature) may indicate delayed maturation in both boys and girls.

Although adolescents are typically uncomfortable about being different from their peers, boys in particular are likely to feel psychologic stress and embarrassment from delayed puberty. Girls who remain smaller and less sexually mature than their peers are not stigmatized as quickly.

If an adolescent appears healthy and has no signs of any disorder—particularly if other family members were slow to mature—the doctor may elect to wait 6 to 12 months before conducting extensive testing. After this time, x-rays are often used to evaluate bone maturity. Adolescents whose bone maturity is delayed are probably just slow overall developers. Those with age-appropriate bone maturity are more likely to have delayed sexual maturation. They require blood tests to measure various hormone levels, as well as tests for diabetes, anemia, and other disorders that can delay sexual development. Sometimes a chromosomal analysis may be performed. Computed tomography (CT) or magnetic resonance imaging (MRI) may be performed to ensure that there is no brain tumor.


The treatment for delayed sexual maturation depends on its cause. Once a chronic underlying disorder has been treated, maturation usually proceeds. An adolescent who is naturally late in developing needs no treatment, although if the adolescent is severely stressed by the lack of development or development is extremely delayed, some doctors may give supplemental sex hormones to begin the process sooner. A genetic disorder cannot be cured, although replacing hormones may help sexual characteristics develop. Surgery may be needed for adolescents with tumors.

Last full review/revision February 2003

Source: The Merck Manual Home Edition