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Changes During Puberty for Boys and Girls

What is puberty? Growing up. Everyone goes through the same process. Whether you start at age 9 or at age 15, it’s all “normal.’’ You are still you inside. Your body and feelings are changing at their own pace. Growing up can be a great experience: a time of changing and finding out who you are. Hormones are responsible for the changes you are beginning to notice. In boys, testosterone is the hormone. In girls, it's estrogen. Girls may start normal puberty as early as age 7 or not start at all until age 15. For boys it is usually anywhere between ages 9 and 15.

Fully developed females
At 18, you'll pretty much have your adult body.

Developing females
At 15, you'll see less difference between you and your friends.

Undeveloped females
At 12, you may have a young girl's body or begin to look like a woman.

Girls

Breasts

Breasts come in all shapes and sizes. Some girls’ breasts grow early; others grow late. Most girls have one breast that grows faster than the other. Breast growth will be the first sign that puberty has started.

  • Your breasts start growing, first with the nipples and the dark area around them (the areolae).

  • Your feet and hands grow next.

  • Then you’ll gain most of your height and muscle.

  • Underarm and pubic hair appear first as downy fuzz, and later grow thicker and darker.

  • Fat (adipose) tissue gives you a curvier shape. You need a certain amount of fat for normal periods.

  • You will begin your menstrual cycle. It is common for your cycle to be irregular. Talk with your doctor if you notice heavy bleeding or have a lot of pain.

  • You may get acne on your face. Talk with your doctor if you are worried about how you look. He or she can prescribe a safe acne medicine or cream to use.

Fully developed males
At 18, you'll see less difference between you and your friends.

Developing males
At 15, you might look like a child or a young man: either one is normal.

Undeveloped males
At 12, you'll probably still have a young boy's body.

Boys

Erection

An erection is the swelling and stiffening of your penis. Erections don’t only happen in sexual situations. It’s also normal to get a “hard on’’ just from your pants rubbing against you.

  • Your testicles start to grow first in puberty. Then your penis grows. First it grows longer, then wider.

  • Hair will then grow in the pubic area.

  • Your feet and hands grow next.

  • Your muscle may double and you gain most of your height.

  • You may have nighttime emissions or "wet dreams."

  • Underarm hair, pubic hair, and facial hair appear first as fuzz, and later grow thicker and darker.

  • Your breast tissue may grow a bit and then shrink.

  • Your voice deepens.

  • You may get acne on your face, chest, or back acne. Talk with your doctor if you are worried about how you look. He or she can prescribe a safe acne medicine or cream to use.

Online Medical Reviewer: Bass, Pat F. III, MD, MPH
Online Medical Reviewer: Adler, Liora C, MD
Date Last Reviewed: 10/1/2016
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