The first signs of puberty in boys​ (and what to know about girls, too)

During puberty, boys and girls start to develop new physical, emotional and social changes, like growth spurts, body shape changes, new body hair, voice deepening and more.^1,2

Here’s what to know about the first signs of puberty in boys, along with helpful information about puberty in girls.

When does puberty usually start?

Every child develops on their own timeline. In general, kids start puberty in their late tweens to early teens. A good way to stay aware is to ask your child to share when they start to notice early signs.²

Boys typically start showing the first signs of puberty between ages 9 and 14.²

In girls, the first signs can start as early as 7 or 8, up to around age 13.²

Early signs of puberty in boys

Puberty is a long, slow process, and the first noticeable changes can vary from child to child.^1,3

A common first sign of puberty in boys is when the testicles start growing larger.³

Common early signs of puberty in boys include:¹

• Increased size of the penis and testicles
• New hair on the face, pubic area and armpits
• A deeper voice
• Muscle growth
• Body odor
• Acne
• More frequent erections and ability to ejaculate
• Ejaculation during sleep (“wet dreams”)

Boys tend to stop growing in height around age 16, though their muscles often continue growing into their 20s.³

Early signs of puberty in girls

The first sign of puberty in females is breast development.

Other common changes during puberty include:¹

• Growing breasts
• First period (menstruation)
• Body odor
• Acne

Other common puberty changes to expect

Puberty affects much more than physical development. Changes also include the way kids think, feel and interact with people and the world around them.⁴

Other changes to expect during puberty include:^1,4

• Growth spurts
• Broader shoulders (in boys)
• Voice cracking (in boys)
• Exploring independence, like asking for more privacy
• Spending more time with friends
• Feeling self-conscious or like they’re being judged
• Irritability or mood changes
• Increased interest in romantic and sexual relationships
• Masturbation

When to talk to a doctor

Most kids who start puberty later than the typical age range typically have a different, healthy pattern of growth. Teens who go through puberty later don’t necessarily need medical treatment. But delayed puberty does warrant investigation and might be a sign of a health condition.²

It’s also a good idea to make an appointment if your child is showing signs of puberty at a younger age than typical.²

Since puberty can come with many emotional changes, check in with your child’s doctor if you notice:

• Emotional changes that concern you, including possible depression
• Significant changes in eating habits
• Concerns they might be thinking about hurting themselves or other people¹

Routine visits to the doctor can also give your child a safe place to ask questions about the changes they’re going through.¹

Takeaway

Puberty is a major milestone in your child’s life. You can support your child by having open, age-appropriate conversations with them about what to expect.¹

Sometimes they might need support learning certain new habits, like how to put on deodorant or manage menstruation. Other times, they may need your emotional support.¹

And remember, it’s a good idea to turn to your pediatrician along the way for regular check-ins and support.¹

At Crystal Run, we believe healthy children make healthy communities. Our Pediatricians partner with parents to offer education on prevention and wellness strategies to keep kids healthy, active and safe. Our expert pediatric team is committed to ensuring every child receives the best care. With extended hours and weekend availability, our pediatricians are available to see children for sick and well visits and provide treatment for common conditions at several pediatric locations throughout the Hudson Valley.

1. FamilyDoctor.org. For parents: What to expect when your child goes through puberty. October 21, 2025.
2. The Endocrine Society. Hormones and childhood growth: What you need to know.
3. Kidshealth.org. Understanding puberty. May, 2022.
4. Healthychildren.org. Stages of adolescence. April 29, 2024.