What is normal puberty?

Normal puberty is when a child’s body starts to grow and develop into a young adult body. There are 2 stages of puberty:

  • Adrenal puberty is when the adrenal glands (small glands on top of the kidneys) cause the first signs of puberty.
  • Gonadal puberty is when the pituitary gland (pea-sized gland in the brain that controls other glands in the body) makes hormones that tell the gonads (testes in boys, ovaries in girls) to make sex hormones (testosterone in boys, estrogen and progesterone in girls). There are 2 types of gonadal puberty: gonadotropin dependent puberty and gonadotropin independent puberty.

What is early puberty?

Early puberty is when a child goes through earlier than expected for their age. Boys go usually through puberty between ages 9-14. Girls usually go through puberty between ages 8-13. In some cases, early puberty is normal. In other cases, a child should see a doctor.

What are the signs of early puberty?

  • In both boys and girls, signs of early adrenal puberty include body odor, underarm hair, pubic hair and acne (pimples).
  • In boys, signs of early gonadal puberty include growth of the penis and testes, more muscle mass, deepening voice and a growth spurt.
  • In girls, signs of early gonadal puberty include breast growth, starting periods and a growth spurt.

What causes early puberty?

The causes of early adrenal puberty and early gonadal puberty are different.

Early adrenal puberty: Sometimes, early adrenal puberty is normal. Other times, a problem with the adrenal glands can cause your son to have early adrenal puberty.

Early gonadal puberty: There are 2 types of early gonadal puberty, which have different causes. These are:

  • Gonadotropin dependent puberty
    This type of puberty is caused by the pituitary gland making the hormones FSH and LH, which tell the testes to make testosterone. This can be caused by tumors, radiation or trauma in the central nervous system or can be idiopathic. This means we have not found a cause of the early gonadal puberty.
  • Gonadotropin independent puberty
    This type of puberty is caused by the testes working on their own or exposure to medication or products with hormones in them.

How do doctors evaluate early puberty in boys?

Our evaluation of your son’s early puberty begins with a discussion about your son’s signs of puberty and a physical exam. If your son has signs of early puberty, we will typically have him get an X-ray of his left hand and wrist called a bone age. A bone age tells us how much your son’s bones have matured. It can also help us figure out if your son should have further evaluation with blood tests.

Your son might have a blood test to help us measure your child’s hormone levels. This will help us figure out if your son has gonadotropin dependent or independent puberty. It will also help us figure out if there is a concern about the adrenal glands. Depending on the results of the laboratory testing further radiology testing may include a head MRI.

Rev. 1/2015

Mass General for Children and Massachusetts General Hospital do not endorse any of the brands listed on this handout. This handout is intended to provide health information so that you can be better informed. It is not a substitute for medical advice and should not be used to treatment of any medical conditions.