School age (5–12 years) · Teen (12–18 years) · Growth & development, Teens
Puberty: what to expect, when, and how to talk about it
Puberty starts between 8 and 13 in girls and 9 to 14 in boys and takes 2 to 5 years. Body changes, growth spurts, mood and sleep shifts are all normal. Signs before 8 in girls or 9 in boys, or none by 13 and 14, deserve a visit.
Key takeaways
- Girls: breast buds first, then hair, growth spurt, then periods about 2 years after breast buds
- Boys: testicles enlarge first, then hair, voice, growth spurt later than girls
- Talk early and often, in small doses; children who hear it from parents first cope better
- Periods that are very heavy, very painful or absent by 15 need a visit
- From 12 or 13, part of each well visit is private time with the doctor
Girls
- Breast buds (small tender lumps under the nipple, often one side first) between 8 and 13: the first sign
- Pubic and underarm hair within about a year
- Growth spurt early in puberty; girls usually reach adult height 2 years after their first period
- First period about 2 to 2.5 years after breast buds, average age 12; irregular for the first 1 to 2 years is normal
- Discharge, body odor, acne, mood swings along the way
Boys
- Testicles enlarge between 9 and 14: the first sign, often unnoticed
- Pubic hair, then penis growth, within a year or so
- Voice cracking, facial and underarm hair, and the growth spurt in mid-puberty, on average 2 years later than girls
- Breast swelling (gynecomastia) in about half of boys, usually gone within 2 years
- Erections and wet dreams are normal and involuntary
Brain, sleep and mood
The teenage brain rewires through the mid-20s, with emotion and reward systems maturing before judgment. Sleep timing shifts later by about two hours, which is biology, not attitude; teens need 8 to 10 hours and most get less. Mood swings are normal; withdrawal, hopelessness, or changes in eating and sleep for more than two weeks are not. See our teen anxiety and depression guide.
How to talk about it
Start before the changes, around 8 or 9, in short conversations that answer the question asked. Use correct words for body parts. Talk in the car, on walks, while cooking, when eye contact is optional. Say what is coming and that it is normal, and keep the door open: “You can ask me anything, and if I don’t know I’ll find out.” Books help; so do we, and we will answer any question a young person brings.
Well visits in the teen years
From about 12, each well visit includes time alone with the doctor. What your teen tells us is confidential, with the exceptions we explain to both of you: safety risks to themselves or others. This is how teens learn to manage their own health, and it is where questions about periods, growth, mood, substances and relationships get honest answers.
When to call us
- Breast development or pubic hair before 8 in a girl, or testicular enlargement before 9 in a boy
- No signs of puberty by 13 in a girl or 14 in a boy, or no period by 15
- Periods that soak a pad every hour, last over 7 days, or cause missed school despite ibuprofen
- Severe acne, or breast swelling in a boy that is painful or one-sided
- Mood changes lasting more than two weeks
Go to the emergency room or call 911 if…
- Heavy bleeding with dizziness or fainting
- Sudden severe testicular pain: possible torsion, go to the ER immediately
Questions parents ask
Is it normal for my daughter’s periods to be irregular?
In the first two years, yes. Cycles from 21 to 45 days are typical early on. By the third year most settle to every 21 to 35 days.
My son is much shorter than his friends. Should I worry?
Boys mature on a wide schedule, and late bloomers often catch up by 16 or 17. We track growth velocity and bone age when a boy has no puberty signs by 14.
Not sure? Ask us
Call or text the office during hours, or send a portal message. For emergencies call 911.
(770) 615-7000Trusted further reading
- HealthyChildren.org (opens in new tab)American Academy of Pediatrics