My daughter just turned eight and is already beginning to grow breasts and hair under her arms. Isn’t she too young for puberty?
It sounds like your daughter is in the early stages of puberty. The first signs are breast bud development, when a mound of tissue forms under the nipple. Around this time, fine pubic and axillary (armpit) hair will develop as well, becoming darker and coarser.
It will spread from the labia to the inner thighs over a few years. After these early signs, it usually takes two or three years for a girl to get her first period, so you and your daughter still have lots of time to get adjusted to these changes in her body.
The average first period is between ages 11 and 12, so your daughter’s development is on track. Most girls develop breast buds around age eight to 11, and it’s normal for a girl to get her first period anywhere up to age 16. It is true that girls are starting puberty earlier than they were in the past—though we don’t fully understand why—but it’s only about six months earlier when compared with girls from generations ago.
Girls typically develop breast buds first, then hair, and then they experience growth spurts and finally periods. If you feel your daughter’s development is atypical—say, she develops hair before breast buds, it’s best to have her examined by a doctor.
In boys, puberty starts around age 10 to 12 and they reach their final height by age 16 to 18. Their transition begins with muscles, which develop while the testes grow; then the penis grows longer and darker, and hair develops on the face, armpits and groin. Lastly, the penis widens and testicles reach their final size.