Precocious Sexual Development
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Precocious Sexual Development

(Precocious Puberty; Premature Puberty)

En Español (Spanish Version)


Girls normally enter puberty between the ages of 8 to 14, while the onset for boys is typically between the ages of 9 to 14. Precocious sexual development or premature puberty means that the physical changes that normally occur during puberty happen earlier.

For girls, this means that before the age of eight they may develop breasts, armpit or pubic hair, mature sex organs, or experience their first period. Premature puberty in boys can mean enlarged sex organs and armpit, pubic, or facial hair, before the age of nine.


While girls are 2 to 5 times more likely to experience premature puberty than boys, most of the time (ie, 90%) there is no known cause. With boys, between 25% to 75% of these cases are due to an underlying reason.

Some known causes of premature sexual development:

Pituitary Gland


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Causes specific to girls:

  • Having ovarian tumor or cysts
  • Taking estrogen
Causes specific to boys:

  • Having tumors on the testicles
  • Taking male sex hormones (androgens)

Other causes:

Risk Factors

Both premature and delayed puberty can run in families. Taking sex hormones can increase the risk of premature sexual development. Some studies have suggested a link between obesity and premature puberty. Other risk factors include head injury, radiation of head, or infection in brain.


One symptom common to both boys and girls is a premature growth spurt in height. Children who experience premature puberty may be taller than their peers. But, in adulthood, they may be shorter because their bones stop growing sooner than normal. Other symptoms include:

  • In girls:
    • Breast development
    • Pubic hair
    • Armpit hair
    • Onset of period
    • Ovary enlargement
    • Cysts on ovaries
  • In boys:
    • Facial hair
    • Armpit hair
    • Pubic hair
    • Penis growth
    • Increased masculinity
    • Testicle enlargement
  • In both girls and boys:
    • Body odor
    • Acne
    • Behavior changes
    • Growth spurt


The doctor will ask about your child’s symptoms and medical history, and perform a physical exam. An assessment of puberty milestones and growth will be performed. An x-ray of the left wrist bone may be taken to assess if bone growth is normal for your child’s age.

Depending on these results, other tests may be ordered, including:

  • Adrenal and pelvic ultrasound
  • MRI of the brain
  • Hormonal levels:
    • In girls: follicle-stimulating hormone (FSH), luteinizing hormone (LH)
    • In boys: testosterone
  • Human chorionic gonadotropin (hCG) levels
  • Thyroid hormone levels if hypothyroidism suspected
  • Growth hormone-releasing hormone (GHRH) stimulation test
  • Dehydroepiandrosterone (DHEA) levels
  • Testicular ultrasound if testicular enlargement is uneven


The treatment for premature sexual development depends upon the cause. For children whose bone age is about the same as their actual age, and in whom no cause can be found, there is no treatment other than continued monitoring and reassurance.


Hormone suppressing medications, including leuprolide acetate, histrelin, nafarelin, work by halting or slowing sexual development. This treatment is often used in children whose bone age is older than their actual age. These medications not only stop sexual development, they also halt the rapid bone growth that can result in the bones closing too soon.

Metformin has also been shown to be effective in delaying puberty.

Psychological Support

Psychological support may be valuable for children who are more physically mature than their peers.


Hormone-producing tumors or other lesions causing premature puberty are usually removed surgically.

Ongoing Monitoring

The doctor will continue to monitor your child’s height, weight, and sexual development to chart the progress and to see if any given treatment has been effective.


Most cases of premature puberty cannot be prevented. To help reduce the chance of your child experiencing precocious sexual development, make sure he or she keeps a healthy weight and is not exposed to or takes sex hormones.


The American Academy of Family Physicians

American Academy of Pediatrics

The Magic Foundation


About Kids Health

Caring for Kids


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Last reviewed March 2008 by David Juan, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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