Group of children, about to start puberty

Puberty & Sexual Development

A child starts their sexual growth at birth. However, many changes start at puberty and continue through adolescence. These changes will include ones that are:

  • sexual
  • physical
  • emotional
  • social

It’s important for you to learn about puberty to support your child as they deal with changes. You’ll be able to let them know that the changes are normal. You’ll also be able to answer their questions openly and correctly. It’s good for kids to know about all types of changes, whether they will experience them themselves or not.


Puberty is when sexual organs mature and making a baby becomes possible. Puberty, and the changes that happen with it, start at different times for different people. Most people start between 8 and 16 years of age.

Hormones in the body start the changes of puberty. Hormones are chemicals that are made by organs called glands. The most important gland is the pituitary gland. This tiny gland, found at the base of the brain, prompts other glands to start making hormones. For some people, the testicles begin to make the hormone testosterone. In others, the ovaries begin to make two hormones, estrogen and progesterone. The pituitary gland also makes human growth hormone. This hormone makes the bones and muscles grow faster during puberty.

Some kids go through puberty quickly, others more slowly. Overall, puberty usually lasts 3 or 4 years. To learn more about the changes kids will go through, see Information by Age.

Give your child the facts about their body and puberty. This will help reassure them that these changes are expected and healthy. They need to know about the changes before they happen. Here are some physical and sexual changes your child can expect:

All kids will:

  • Start growing taller and gain weight (both fat and muscle).
  • Start making more oil on their skin. Acne may start on their face, upper back and/or chest.
  • Grow hair on their legs, underarms and pubic area. This will continue to grow thicker and darker during puberty.
  • Start to sweat more and may need to start using an antiperspirant or deodorant.
  • Have a new interest in sex brought on by changes in hormones.
  • May masturbate.

Changes in kids born with ovaries and a uterus:

  • They grow taller faster than those born with testicles. They will usually reach their adult height by age 16 or 17.
  • Breasts will start to grow, and they may experience soreness under the nipples.
  • They will gain fat in their hips, buttocks, legs and stomach.
  • Menstrual periods will start and become regular in time. Usually, periods start 2 to 2.5 years after breasts begin to grow.
  • They will start to have a white, mucous-like discharge from their vagina.

Changes in kids born with a penis and testicles:

  • Their shoulders will grow wider.
  • Body hair and facial hair will start to grow.
  • Their penis, scrotum, and testicles will grow.
  • Their testicles start producing sperm.
  • Their voice will start to crack and become deeper.
  • They may have swelling under the nipples (this growth usually goes away by the end of puberty).
  • Erections take place more often during this time.
  • Ejaculation and nocturnal emissions (‘wet dreams’) will occur. Ejaculation is when the penis releases semen. Nocturnal emissions are when the semen is released during sleep.
Unexpected erections and nocturnal emissions can embarrass your teen. Erections may have bad timing (like in front of the class) and nocturnal emissions may also be concerning. Reassure your teen that these changes are just a part of maturing and will occur less often with time.


Menstruation (‘having your period’) is a physical change that will start at some point during puberty.

The body begins releasing one egg cell (or ovum) from the ovaries each month. If a sperm cell fertilizes this egg cell, it can grow into a baby.

To get ready for a fertilized egg, the uterus builds up a thick lining of blood and tissue. This lining is where the fertilized egg would implant and grow into a baby.

If a sperm cell doesn’t fertilize the egg cell, it breaks down. The lining of the uterus isn’t needed so it begins to shed. In a few days, the lining leaves the body through the vagina (menstruation) and the cycle starts all over again. The cycle is between 24 and 38 days. A period is the time the blood and tissue leave the body though the vagina. It usually lasts between 3 and 5 days.

Every person is different. There’s no right or wrong age for menstruation to start.

Here are some things you can talk about to make sure your child is ready:

  • Explain menstruation to your child before their periods start. Make sure they know that getting their period is a normal part of growing and changing.
    • They can keep doing their usual activities during their period.
  • Some people get mild to strong cramps with their periods. Using heat (a hot water bottle or heating pad) can help. Some over-the-counter pain medications like ibuprofen (e.g., Advil® or Motrin®) or naproxen (Midol®) may help. If your child has a lot of pain with their period, talk to your health care provider.
  • Describe what premenstrual syndrome (PMS) is and what they might experience along with their period, such as bloating, diarrhea, sensitive breasts, or mood changes.
  • Explain why it’s important to change pads/tampons/cups regularly.  Make sure your child knows they can and should continue with regular bathing during their period. Other things you can do:
    • Show your child how using a calendar, diary or phone app to keep track of their cycle will help them be ready for the next one.
    • Have a supply of pads and tampons ready to show your child. The smallest size tampon with an applicator is the easiest for beginners.
    • Tampons need to be changed regularly. Leaving one in longer than 8 hours increases the likelihood of toxic shock syndrome (TSS), a very rare but serious illness.
    • Suggest your child keep a period pack (clean underwear, pads/tampons, wipes) in a nearby place (backpack or locker) in case of an unexpected period.


If you talk openly about periods in your family, this helps reduce the stigma or the shame that people sometimes associate with menstruation. Other ways you can reduce stigma:
  • Leave period supplies on an open shelf instead of hiding them underneath the sink.
  • Speak openly about periods rather than using euphemisms like “a visit from Aunt Flo”, “shark week” or “crimson tide”.
  • Put period supplies like tampons openly on the shopping list instead of giving them nicknames like “marshmallows”.
  • Treat a leak like an unfortunate occurrence and not something embarrassing.


Helpful Tools


A Hard Pill to Swallow

Julie accidentally drops something she wishes her dad hadn’t seen. How does Dad respond? Watch our webisode to find out; and learn how to start the conversation on sexual health.


The Hair Down There

Ryan asks Mom about ‘the hair down there’ for the first time. How will she respond? Watch our webisode to find out; and learn how to start the conversation on sexual health.

Jump to:

Back to top