Jeff hates gym class. It's not that he minds playing soccer or basketball or any of the other activities. But he does dread going into the locker room at the end of class and showering in front of his friends. Although the other guys' bodies are growing and changing, his body seems to be stuck at a younger age. He's shorter than most of the other guys in his grade, and his voice hasn't deepened at all. It's embarrassing to still look like a little kid.

Abby knows what it's like to feel different, too. The bikini tops that her friends fill out lie flat on her. Most of them have their periods, too, and she hasn't had even a sign of one.

Both Jeff and Abby wonder if there's anything wrong.

What Is Delayed Puberty?

Puberty is the time when your body grows from a child's to an adult's. You'll know that you are going through puberty by the way that your body changes.

If you're a girl, you'll notice that your breasts develop and your pubic hair grows, that you have a growth spurt, and that you get your period (menstruation). The overall shape of your body will probably change, too — your hips will widen and your body will become curvier.

If you're a guy, you'll start growing pubic and facial hair, have a growth spurt, and your testicles and penis will get larger. Your body shape will also begin to change — your shoulders will widen and your body will become more muscular.

These changes are caused by the sex hormones (testosterone in guys and estrogen in girls) that your body begins producing in much larger amounts than before.

Puberty takes place over a number of years, and the age at which it starts and ends varies widely. It generally begins somewhere between the ages of 7 and 13 for girls, and somewhere between the ages of 9 and 15 for guys, although it can be earlier or later for some people. This wide range in age is normal, and it's why you may develop several years earlier (or later) than most of your friends.

Sometimes, though, people pass this normal age range for puberty without showing any signs of body changes. This is called delayed puberty.

What Causes Delayed Puberty?

Puberty can be delayed for several reasons. Most often, it's simply a pattern of growth and development in a family. A guy or girl may find that his or her parent, uncle, aunt, brothers, sisters, or cousins developed later than usual, too. This is called constitutional delay (or being a late bloomer), and it usually doesn't require any kind of treatment. These teens will eventually develop normally, just later than most of their peers.

Medical problems also can cause delays in puberty. Some people with chronic illnesses like diabetes, cystic fibrosis, kidney disease, or even asthma may go through puberty at an older age because their illnesses can make it harder for their bodies to grow and develop. Proper treatment and better control of many of these conditions can help make delayed puberty less likely to occur.

A person who's malnourished — without enough food to eat or without the proper nutrients — may also develop later than peers who eat a healthy, balanced diet. For example, teens with the eating disorder anorexia nervosa often lose so much weight that their bodies can't develop properly. Girls who are extremely active in sports may be late developers because their level of exercise keeps them so lean. Girls' bodies require a certain amount of fat before they can go through puberty or get their periods.

Delayed puberty can also happen because of problems in the pituitary or thyroid glands. These glands produce hormones important for body growth and development.

Some people who don't go through puberty at the normal time have problems with their chromosomes, which are made up of DNA that contain our body's construction plans. Problems with the chromosomes can interfere with normal growth processes.

Turner syndrome is an example of a chromosome disorder. It happens when one of a female's two X chromosomes is abnormal or missing. This causes problems with how a girl grows and with the development of her ovaries and production of sex hormones. Women who have untreated Turner syndrome are shorter than normal, are usually infertile, and may have other medical problems.

Males with Klinefelter syndrome are born with an extra X chromosome (XXY instead of XY). This condition can slow sexual development.

What Do Doctors Do?

The good news is that if there is a problem, doctors usually can help teens with delayed puberty to develop more normally. So if you are worried that you're not developing as you should, you should ask your parents to make an appointment with your doctor.

In addition to doing a physical examination, the doctor will take your medical history by asking you about any concerns and symptoms you have, your past health, your family's health, any medications you're taking, any allergies you may have, and other issues like growth patterns of your family members. He or she will chart your growth to see if your growth pattern points to a problem and also may order blood tests to check for thyroid, pituitary, chromosomal, or other problems. You may also have a "bone age" X-ray, which allows the doctor to see whether your bones are maturing normally.

In many cases, the doctor will be able to reassure you that there's no underlying physical problem; you're just a bit later than average in developing. If the doctor does find a problem, though, he or she might refer you to a pediatric endocrinologist, a doctor who specializes in treating kids and teens who have growth problems, or to another specialist for further tests or treatment.

Some teens who are late developers may have a difficult time waiting for the changes of puberty to finally get going — even after a doctor has reassured them that they are normal. In some cases, doctors may offer teens a short course (usually a few months) of treatment with hormone medications to get the changes of puberty started. Usually, when the treatment is stopped a few months later, the teen's own hormones will take over from there to complete the process of puberty.

Dealing With Delayed Puberty

It can be really hard to watch your friends grow and develop when the same thing's not happening to you. You may feel like you're never going to catch up. People at school may joke about your small size or your flat chest. Even when the doctor or your parents reassure you that things will be OK eventually — and even when you believe they're right — it's difficult to wait for something that can affect how you feel about yourself.

If you're feeling depressed or having school or other problems related to delays in your growth and development, talk to your mom or dad, your doctor, or another trusted adult about finding a counselor or therapist you can talk to. This person can help you sort out your feelings and suggest ways to cope with them.

Delayed puberty can be difficult for anyone to accept and deal with — but it's a problem that usually gets solved. Ask for help if you have any concerns about your development. And remember that in most cases kids will eventually catch up with their peers.

Reviewed by: Steven Dowshen, MD
Date reviewed: August 2011