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Early Puberty Signs

The signs of early puberty and puberty are usually the same. It's the timing that's different. Signs include:

In girls

  • Breast development (which is often the first sign)
  • Menstruation (typically not until two to three years after the earlier symptoms start)

In boys

  • Growth of the testicles, penis, and scrotum
  • Facial hair and underarm hair, and a deepening voice  (usually late signs of puberty)

Growth spurts are another sign of early puberty in both boys and girls.

 

Causes of Central Precocious Puberty

In most cases, experts don't know what causes central precocious puberty. 

Sometimes, central precocious puberty is triggered by a medical problem. Underlying causes are more common in boys and children under 6. They can include: 

  • Tumors and other growths, which are often benign
  • Brain injury, either from surgery or a blow to the head, that affects hormonal balances
  • Inflammation of the brain, sometimes from an infection 

That probably looks like a worrisome list. Just remember that only in a small number of cases in boys is central precocious puberty caused by a medical problem. In girls it is extremely rare for a medical problem to be the cause.

Early Puberty: Related Factors

While they aren't necessarily causes, a number of factors seem to be related to early puberty. They include: 

  • Gender. Girls are 10 times as likely to have central precocious puberty as boys.
  • Genetics. Occasionally precocious puberty can be triggered by genetic mutations that trigger the release of sex hormones. Most often these children have a parent or sibling with similar genetic abnormalities. 
  • Race. Researchers don’t know why, but on average African-American girls seem to start puberty about a year earlier than white girls. Some experts say that puberty should only be considered early in African-American girls if it happens before age 6.  
  • International adoption. One study showed that children who are adopted from overseas are 10-20 times more likely to develop precocious puberty. Again, experts aren't sure why, but the uncertainty of the exact ages of the adopted children might bias the study results. 
  • Obesity. A number of studies have shown an association between obesity in young girls and an increased risk of precocious puberty. However, researchers don't know how direct the link is. Obesity does not seem to be connected to early puberty in boys. 

It's possible that chemicals in our environment could be playing a role in early puberty. Some researchers have focused on bisphenol A (BPA), a chemical in some plastics. Studies in animals have shown it can affect puberty and fertility. For now, scientists don't know if chemical exposure plays a role in early puberty or not. 

Puberty: What's Normal?

When should puberty start? See the ages and changes to expect.
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