A lot of changes happen as you grow up, especially as you reach puberty (say: pyoo-bur-tee), the name for the time when your body begins to develop and change. Girls start developing breasts and get their periods — signs they are growing into women.

But how do boys know they are growing into men? Let's find out.

For a guy, there isn't just one event or sign that you're growing up. There are lots of them, including your body growing bigger, your voice changing, and hair sprouting everywhere. Most boys begin puberty between the ages of 9 and 14. But keep in mind that puberty starts when a boy's body is ready, and everyone grows at his own pace.

Here are some of the questions boys have.

Why Are Girls Taller Than Me?

You might have noticed that some of the girls you know are taller than the boys. But you've probably noticed that out of the adults you know, most of the men are taller than the women. What's going on?

Well, girls get a head start on puberty — and growing taller — because they usually start these changes between the ages of 8 and 13. Most boys, on the other hand, don't begin until between the ages of 9 and 14. So that's why girls are often taller than boys during that time.

Most boys may catch up — and even grow taller than girls. But it's also important to remember that your genetics play a role in height. So if your mom and dad are tall, you're more likely to be tall. And if your mom and dad are kind of short, you may be short, too. But nothing is definite.

You have to wait and see how it turns out, but you can also talk to a doctor if you're concerned. Remember — not every adult male is tall. Many men who are considered "short" have gone on to have careers in the movies, the military, and even professional basketball!

There aren't any exercises or magic pills to make you grow tall. But by being active and eating nutritious foods, you're helping your body grow up healthy, just the way it should.

When Will I Get Muscles?

During puberty, some boys might become worried about their bodies after seeing what some of their friends look like. For instance, lots of boys are concerned about their muscles. You may have already noticed some boys starting to get chest muscles (called the pectoralis muscles or pecs for short). Others may have broad shoulders (the deltoids, or delts for short). Other boys might still be slimmer and smaller.

Remember that puberty happens on its own schedule, so there's no rushing it if you're a little slower to develop muscles. Maybe you've considered lifting weights to help yourself get bigger. It's important to know that if you haven't quite reached puberty, this will tone your muscles, but it won't build up any muscles yet.

Eating nutritious food and being active (like riding your bike, swimming, and playing sports) will help you be a kid who's strong and fit. In time, you'll reach puberty and you can start building your muscles, too.

If you decide to try lifting weights, first let your doctor know you are interested. He or she may tell you to hold off on weightlifting for a bit or give you some advice on how to start. If your doctor discourages weightlifting, try some other ways to work out. Resistance bands, which are like big rubber bands, are a great way to help build your strength without putting too much strain on your muscles.

If your doctor recommends weightlifting, here are some tips:

• Have a qualified coach or trainer supervise you. It's smart to have somebody show you the proper way to lift weights. This will help you gain strength and prevent injury.
• Use lighter weights. Your coach or trainer can recommend the right amount. Lifting heavy weights can cause injuries and then you'll have to wait until you recover before you can work out again.
• Do repetitions. It's better to lift a smaller amount of weight a bunch of times than to try to lift a heavy weight once or twice.
• Rest. Let your body have a break at least every other day.

Do I Think About Girls Too Much or Not Enough?

There is this girl who lives in your neighborhood and you see her playing with her friends every afternoon when school is done. You get really hot and your palms sweat when she says "hi" to you. That night you go to bed and before you sleep, you have one last thought about her. Every day for the next few weeks you keep thinking about her. You might be wondering, "Why do I feel this way?" You just may have a crush.

Or perhaps your friend keeps talking about this one girl he thinks is so pretty. He goes on and on about how she tells funny jokes. He also tells you that he likes her. You think, "Why don't I feel or talk this way about a girl — am I supposed to?"

Every boy has his own likes and dislikes. And during puberty, some boys are very friendly with girls and others might be nervous about talking to girls. Thinking about someone you like is a normal process of puberty. And if you feel like you don't like any girls, that's fine, too. Eventually, you may find someone who makes you feel giddy inside. Only time will tell.

So why do you feel this way? The hormones in your body are becoming more active. As a result, you're starting to have more feelings. These feelings can confuse you and may leave you scared. This is natural because you are going through a new phase in your life.

Talking with a friend or an older person like your brother or sister might help you be less confused. Older people sometimes have more experience than you, so they can be good people to go to for advice.

What's Up With Body Hair?

Body hair really gets going during puberty. Some boys will start to notice hair growing on their face around the chin, on the cheeks, and above the lip. Also, hair grows on the chest, the armpits, and even down there in the pubic region. Remember that there's nothing to worry about because hair is just one of the body's many ways of telling you that you are on your way to manhood.

You're growing hair in new places because hormones are telling your body that it is ready to change. Some of the hormones that trigger this new hair growth come from your adrenal glands. Other hormones come from your pituitary (say: puh-too-uh-ter-ee) gland (a pea-shaped gland located at the bottom of your brain). These pituitary hormones travel through your bloodstream and make your testicles ("balls") grow bigger and start to release another hormone called testosterone that also helps make your body start sprouting hair in your pubic area, under your arms, and on your face.

Boys don't really need to do anything about this new hair that's growing. Later, when you're a teen, and the hair gets thick enough on your face, you may want to talk with your parents about shaving.

Do I Smell?

You probably know what sweat is, but did you know that it's also called perspiration (say: pur-spuh-ray-shun)? How does it happen? Perspiration comes out of your skin through tiny holes called pores when your body gets hot.

Your body likes a temperature that is 98.6°F (37°C). If you get hotter than that, your body doesn't like it, so then your body sweats. The sweat comes out of the skin, then evaporates (this means it turns from a liquid to a vapor) into the air, which cools you down. Sometimes this sweat or wetness can be smelly and create body odor (sometimes called BO). During puberty, your hormones are working all the time, which explains why you sweat a lot and, well, sometimes smell.

What makes it smelly? The sweat is made almost completely of water, with tiny amounts of other chemicals like ammonia (say: uh-mow-nyuh), urea (say: yoo-ree-uh), salts, and sugar. (Ammonia and urea are left over when your body breaks down protein.) Sweat by itself is not really smelly, but when it comes in contact with the bacteria on your skin (which everyone has) it becomes smelly.

But how can you keep yourself from being all sweaty and smelly? First, you can shower or bathe regularly, especially after playing sports or sweating a lot, like on a hot day. You can also use deodorant under your arms.

Deodorant comes in many good-smelling scents or you can use one that's unscented. Some deodorants come in a white stick that you can twist up. Lots of people put this on after showering or bathing before they put their clothes on. Otherwise, the white stick deodorants can leave white marks on your clothes. You can also choose a deodorant that's clear instead of white.

You can decide to wear a deodorant (which helps stops the smell) or a deodorant/antiperspirant (which helps stops the smell and the sweat). If you find these products aren't working for you, talk with your doctor.

What About Erections?

An erection is what happens when your penis fills up with blood and hardens. The penis will become bigger and stand out from the body. Boys will start to notice erections occurring more often when they reach puberty. And they're perfectly normal.

An erection can happen at any time. You can get many in one day or none at all. It depends on your age, sexual maturity, level of activity, and even the amount of sleep you get.

An erection can happen even when you're sleeping. Sometimes you might wake up and your underwear or bed is wet. You may worry that this means you wet your bed like when you were little, but chances are you had a nocturnal emission, or "wet dream." A wet dream is when semen (the fluid containing sperm) is discharged from the penis while a boy is asleep. Semen is released through the urethra — the same tube that urine (pee) comes out of. This is called ejaculation.

Wet dreams occur when a boy's body starts making more testosterone. This change for boys is little bit like when a girl gets her period. It's a sign a boy is growing up and the body is preparing for the day in the future when a man might decide to be a father. Semen contains sperm, which can fertilize a woman's egg and begin the process that ends with a baby being born.

Although some boys might feel embarrassed or even guilty about having wet dreams, a boy can't help it. Almost all boys normally experience them at some time during puberty and even as adults.

But if you ever have pain or a problem with your penis or testicles, it is important that someone take you to the doctor.

You may think "Man, I don't want to go to the doctor for that!" But it's best to get problems like this checked out — and your doctor won't be embarrassed at all. It's a doctor's job to help you take care of your body — even that part.

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