A study published last year by the American Academy of Pediatrics suggests that boys are now reaching puberty at the average age of 10, about 1½ years earlier than previous generations.
“The earliest normal age for the onset of puberty is 8 for girls and 9 for boys,” said Dr. Cydney Fenton, director of Akron Children’s Center for Diabetes and Endocrinology. “While the average age for reaching puberty may be younger, there’s still a wide range of what’s considered normal.”
For girls, puberty is defined by the start of menstruation, breast development and growth spurts, with breast development being the first sign. Body odor and pubic and armpit hair are not necessarily signs of puberty in girls, as the adrenal glands which trigger these changes can kick in sooner.
Although girls may be entering puberty earlier, the average age for menstruation is still around 12. Some girls will reach this milestone later.
If by age 16 your daughter has not had a period, talk to her doctor.
For boys, the onset of puberty is primarily marked by testicular enlargement.
“Because pediatricians do not routinely perform testicular exams or measure testicular volume, it’s traditionally been harder to detect the start of puberty in boys,” said Dr. Fenton. “Without regular exams of the testes, it can be easy to miss subtle changes.”
By the time a boy is 13 or 14, he should have pubic hair. Genital growth should also have occurred by age 14.
Although doctors don’t know why, the onset of puberty varies by race, with African-American boys and girls starting earlier than children of other races. However, although African-American girls tend to get their first period sooner, the median age for them has dropped slightly.
Over the years, the trend toward early puberty was attributed to improved nutrition and better living conditions. Today, the reasons may not be due to positive changes.
Although there are no clear-cut answers, many theories exist regarding exposure to chemicals in food and water, changes in diet, decreased physical activity and the rise in childhood obesity, all of which might interfere with normal hormone production.
However, none of these theories have been proven.