Puberty: When It Happens, What Changes, and When It Comes Early or Late

Puberty is the time of life when a child becomes sexually mature. It brings physical changes, which differ between girls and boys.

When it happens

It usually begins between ages 8 and 13 in girls and 9 and 14 in boys.

The changes

In girls:

1. Breast development is usually the first sign.
2. Hair then grows in the pubic area and armpits.
3. Menstruation — the first period — usually comes last.

In boys:

1. The testicles and penis usually grow first.
2. Hair then grows in the pubic area and armpits.
3. As puberty goes on, muscles grow, the voice deepens and facial hair develops.

In both: acne is common, and there is usually a growth spurt — a rapid increase in height — lasting about 2 or 3 years, which brings children close to the adult height they reach after puberty.

Early and late puberty

• Precocious puberty starts earlier than normal: before age 8 in girls and before age 9 in boys. Children affected may not reach their full height, because their growth stops too soon, and some have psychological or social problems, such as anxiety about being different from their peers — though many do not, especially when puberty begins only slightly early.
• Delayed puberty starts later than the normal range. Many children with it go through an otherwise normal puberty, just late. Others have a long-lasting condition, hypogonadism, in which the sex glands — the testes or ovaries — make few or no hormones.

Sources

• MedlinePlus, U.S. National Library of Medicine, "Puberty," drawing on the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). https://medlineplus.gov/puberty.html
• NICHD, "About Puberty and Precocious Puberty." https://www.nichd.nih.gov/health/topics/puberty/conditioninfo
• Rewritten in hubnx's own words.