Recent research suggests that puberty may be happening earlier for both boys and girls. On average, girls will begin puberty around age 11 and boys around age 12. However, it is considered typical for puberty to begin any time between ages 8 and 14.

If puberty begins earlier, it might signify a condition called precocious puberty. This is when puberty begins before age 8 in girls and age 9 in boys. Precocious puberty is a rare condition that may require treatment.

Learn about why puberty might be happening earlier, the signs and causes of precocious puberty, and the outlook for children with this condition.

Language matters

Sex and gender exist on spectrums. This article will use the terms “girl” and “boy” to refer to a person’s sex assigned at birth.

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The standard age of puberty onset may be decreasing for both boys and girls.

A 2020 research review analyzed 30 studies that examined the onset of breast budding, known as thelarche, in girls.

Menarche, a girl’s first menstrual period, has been studied as a marker of the onset of female puberty. However, the researchers note that a first period can occur later in puberty and might not be a good indication of puberty onset. Another concern is that studies often rely on adult memories of menarche, which may be less accurate.

Instead, the researchers argue that thelarche is the most important early indicator of puberty. This is used in clinical evaluations to distinguish between girls who are prepubescent and pubescent. Assessing breast development is also used to distinguish between precocious puberty and regular onset puberty.

The researchers found that the age of breast budding decreased by nearly 3 months for every decade between 1977 and 2013, suggesting that puberty is occurring earlier now than in the 1970s.

The authors of the study suggest that possible reasons for the earlier onset of puberty could be:

  • environmental influences
  • the obesity epidemic
  • exposure to endocrine-disrupting chemicals

A 2019 study examined the height and growth of more than 4,000 boys in Sweden between 1947 and 1996.

The study used peak height velocity, or the timing of a pubescent growth spurt, as a marker for puberty. They found that the boys who were born in the latter part of that period began puberty earlier. For every decade that went by, boys reached their peak height velocity 1.5 months earlier.

The authors of the study argue the increase in childhood BMI could be a factor in the earlier onset of puberty.

Precocious puberty is a condition that occurs when children reach puberty earlier than expected. This happens when girls experience signs of puberty before age 8 and boys experience signs of puberty before age 9.

Children who experience early onset puberty face a number of potential challenges. They have bone growth and skeleton maturation at an earlier age than their peers. When puberty ends, growth stops.

In the initial stages of puberty, children with precocious puberty may have a growth spurt and be taller than their peers. But they may also stop growing too soon and not reach their full height potential.

Children who go through precocious puberty may also experience a variety of emotional and social challenges.

Girls who develop breasts and begin their periods much earlier than their peers may be embarrassed and experience teasing and body shaming. They might also be irritable and moody.

Boys who go through puberty early can be aggressive. Children with precocious puberty may also display signs of defiance during this time.

They may also experience an earlier sex drive than their peers. This can be difficult for children to mentally cope with and can become a concern if they act on sexual impulses that may not be appropriate for their age.

Treatment for central precocious puberty may not always be necessary, but it is available for puberty that begins at a very early age. Treatment lowers sex hormone levels to slow or stop puberty.

Speak with your child’s pediatrician if you notice signs of puberty before the expected age.

In the majority of cases, the cause of precocious puberty is unknown.

Precocious puberty can be triggered by an area of the brain called the hypothalamus. This part of the brain sends signals to the pituitary gland to release hormones that trigger the ovaries or testicles to make sex hormones.

In precocious puberty, the brain begins sending these signals earlier than it should.

This can happen for a variety of reasons. One known cause is a mutation in the MKRN3 gene. This gene plays a role in determining when puberty begins. This genetic mutation can be passed down in families. In roughly 5 percent of boys, precocious puberty is inherited.

Factors related to the brain may also cause precocious puberty. These include:

  • trauma to the brain
  • infection
  • cancer treatment or other radiation
  • brain tumor
  • other atypical brain developments

Entering puberty too early may also be the result of an ovary or thyroid gland concern in girls. Genetic disorders like McCune-Albright Syndrome are another potential cause.

In girls, 90 to 95 percent of cases of precocious puberty have no known cause. In boys, a cause can more often be identified.

Signs of precocious puberty in girls may include:

  • menstruation beginning before age 10
  • breast development before age 8
  • growth spurt before age 8

In boys, signs of precocious puberty include:

  • growth spurt before age 9
  • enlargement of the penis or testicles before age 9

In both boys and girls, there are some changes that could be related to precocious puberty but may also just be typical development signs. These include:

  • a more mature body odor
  • pubic, underarm, or facial hair
  • deepening of the voice
  • acne

Children who are female with overweight or obesity are more at risk for precocious puberty than other children.

Recent research suggests that puberty may be happening earlier now than it was in the past. It is considered standard for puberty to begin between ages 8 and 14.

Puberty that happens unusually early is called precocious puberty. Precocious puberty happens before age 8 in girls and age 9 in boys.

The cause of precocious puberty is often unknown but may be due to:

  • genetics
  • environmental factors
  • an underlying health condition

Children who have precocious puberty may experience a variety of challenges, including not reaching their potential height, social and emotional concerns, and challenges related to an early onset sex drive.

Speak with your child’s pediatrician if you notice signs of puberty earlier than the expected age.