Does Puberty Start Earlier Than It Used to?

Tricia Christensen
Tricia Christensen

Evidence gathered from scientists clearly suggests that puberty begins earlier than it used to. Some of this evidence evaluates the falling age of menarche, which is the onset of a girl’s menstruation. Other evaluations consider the first ejaculatory erections of boys, or the general onset of puberty symptoms like breast buds, and the growth of pubic hair.

The average age of a girl's first menstruation is 12.2 years.
The average age of a girl's first menstruation is 12.2 years.

In evaluating menarche, the average age first menstruation begins is 12.2 years, in most Western countries. In contrast, approximately 100 years ago, the average age of puberty as assessed by first menstruation was 13.9 years old. This is clearly a significant difference.

Better nutrition may be responsible for early puberty.
Better nutrition may be responsible for early puberty.

While consistently a larger percentage of girls begin puberty sooner than boys, evidence suggests that boys may also go through it sooner. About 7% of boys reach sexual maturity by the age of eight. Even 40 years ago, less than 1% of boys reached sexual maturity by that age.

Some reasons have been suggested for early puberty. Better nutrition is considered a leading cause. More body fat and more body mass means the body is physically ready to begin this stage. However, excess body fat due to less exercise often leads to early development as well.

Some suggest that chemicals present in food, like hormones given to animals that are then consumed by humans, may result in earlier development of puberty. As well, some studies have shown that stress actually corresponds with earlier puberty, particularly among girls.

Earlier age of puberty should not be confused with the medical definition of precocious puberty. This is defined as premature onset of sexual development. Girls entering puberty prior to being eight years old, and boys who start prior to the age of nine, are thought to have precocious puberty. This condition is most likely to occur among girls who are obese. However, it may also be genetic. Sometimes premature development, especially in very young children indicates tumors causing hormonal imbalance or production.

Precocious puberty can be extremely challenging, particularly for young girls. Their rapid maturation does create notice among peers and may cause social difficulties. However, early signs, like breast buds, may not always be followed by early onset of menarche.

Particularly in girls, those who seem to go through puberty later, and have later menarche rates often are very active in sports, small in build, or who have mothers with a later menarche rate. It is not uncommon for girls who are competitive athletes to begin their periods after the age of 15 or 16.

It's not uncommon for girls who are competitive athletes to begin menstruating after the age of 15 or 16.
It's not uncommon for girls who are competitive athletes to begin menstruating after the age of 15 or 16.
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


BrickBack - I agree with you. I have talked to both of my children and they are seven and nine about what to expect.

I know boys begin to develop puberty facial hair. My son is only seven and has a little hair above his lip. I don’t know if this is related to the hormonal changes although I think it is a bit early.

He loves it when I point it out to him because he thinks that he is becoming a man and gets excited. I think if you talk to children about their changes they actually look forward to puberty development.

My daughter’s pediatrician also said that puberty in females is based on hereditary so whenever the mother had puberty is most likely when the daughter is going to have puberty.


I wanted to say that I recently read that during puberty females can gain about 40 pounds and males gain about 43 pounds between the ages of ten and fourteen.

They can also grow about nine inches as well. Puberty development is an awkward stage in a child’s life because so many things are happening within the child’s body all at once. Girls start to produce more estrogen while boys begin producing more testosterone.

It is really a good idea to talk to your kids about these changes ahead of time so they know what to expect and are not scared. A girl that experiences an early menstruation period might not understand what is going on and may be frightened especially if none of her friends are experiencing it yet.

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