Skip to content

You might think that diagnosing early puberty is simple. If your 6-year-old daughter seems to be developing breasts or your 7-year-old son has hair under his arms, isn't that evidence enough?

Actually, it's not. Early puberty can be hard to diagnose, even for the experts. So how do doctors settle on a diagnosis and treatment plan for precocious puberty? Here’s a rundown of some of the things they might consider. 

Is It Early Puberty?

Puberty is considered precocious when it starts, on average, in girls younger than 8 and boys younger than 9. Estimates vary, but some experts say that early puberty affects about 1 out of 5,000 children.

"Of all the kids who are referred to me for signs of early puberty, only about 10% of them have true precocious puberty," says Paul Kaplowitz, MD, PhD, chief of the division of endocrinology at Children's National Medical Center in Washington D.C. "A lot of the parents who come in are very anxious without good cause."

Many of the kids Kaplowitz sees have conditions like premature thelarche and premature pubarche. These can cause, respectively, isolated breast development and pubic hair without other symptoms. These conditions are not signs of puberty, but just normal variations, Kaplowitz says.

If you think your child is showing signs of early puberty, don't make assumptions, says Jami Josefson, MD, an endocrinologist at Children's Memorial Hospital in Chicago. Ask your pediatrician for a referral to an expert, like a pediatric endocrinologist.

Diagnosing Early Puberty

There are two kinds of early puberty. The more common form is central precocious puberty. This is when the brain starts the normal process of puberty -- triggering the release of various hormones -- but does it early. In most cases, there is no known reason. Very rarely, central precocious puberty has a medical cause, like an infection or growth in the brain. 

Peripheral precocious puberty is less common. It usually develops when a problem with the ovaries or testicles -- like a cyst or a tumor -- triggers the release of the hormones estrogen or testosterone. 

To diagnose early puberty, your child's doctor will ask some questions and run some tests. They might include:

  • A physical exam, to evaluate any changes in the body.
  • A family history, to find out if early puberty might run in the family.
  • Blood tests, which check a child's hormone and sometimes thyroid levels.
  • X-rays, usually of the hand and wrist, to check a child's bone age. This is a way of seeing how quickly he or she is growing.
  • MRIs of the brain. These are sometimes used to rule out medical problems that could cause central precocious puberty, like tumors. MRIs are not routine for most kids. They're used when an underlying cause is more likely, as in children under 6 or kids with other symptoms.
  • Ultrasounds -- of the ovaries, for instance -- can be helpful in some cases.

Puberty: What's Normal?

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