A lot of changes happen as you grow up, especially as you reach puberty (say: PYOO-bur-tee). This is the time when your body begins to develop and change.

During puberty, 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 puberty starts when the body is ready. Everyone grows at their own pace.

Here are some common questions about boys and puberty.

How Tall Will I Be?

Your genes play a role in your height. Look at your mom, dad, and other relatives to get an idea of your growth. But nothing is definite. You have to wait and see how it turns out. You can always ask your doctor if you have questions about your height. 

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

Some boys notice that girls grow taller before they do. That's because girls get a head start on puberty — and growing taller — because they usually start these changes between the ages of 8 and 13. 

When Will I Get Muscles?

You may have already noticed some boys starting to get chest muscles (called the pectoralis muscles or pecs for short). Some 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. If you haven't quite reached puberty, things like lifting weights will tone your muscles, but won't build up any muscles yet.

Eating healthy 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 if you want.

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 says weightlifting is OK, 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.

What About Crushes?

Is there someone you can't stop thinking about? Maybe you feel flushed or get sweaty palms when they say "hi." Or maybe your friends talk about their crushes and you think, "Why don't I feel or talk this way about someone? Am I supposed to?"

Every boy has his own likes and dislikes. Thinking about someone you like is a normal part of puberty. And if you don't have anyone you like that way, that's fine, too. It's all normal.

So why do people 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 be confusing. That's natural. 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. 

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).

Pituitary hormones travel through your bloodstream. They make the 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 and that it's also called perspiration (say: pur-spuh-RAY-shun)? How does it happen? Sweat comes out of your skin through tiny holes called pores when your body gets hot.

During puberty, your hormones are working all the time. This explains why you sweat a lot. Sweat is made almost completely of water with tiny amounts of other chemicals. Sweat by itself is not really smelly. But when it comes in contact with the bacteria on skin (which everyone has) it becomes smelly.

How can you keep yourself from being all sweaty and smelly? First, 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 scents or you can use one that's unscented. 

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 don't work for you, talk with your doctor.

What About Erections?

An erection happens when the penis fills up with blood and hardens. The penis will become bigger and stand out from the body. Boys may start to notice erections more often when they reach puberty. They are 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 find you had a "wet dream." A wet dream is when semen (the fluid containing sperm) comes out of the penis during sleep. Semen is released through the urethra — the same tube that urine (pee) comes out of. This is called ejaculation.

Wet dreams happen when a boy's body starts making more testosterone. It's a sign the body is preparing for 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.

You can't help having wet dreams, and they are nothing to be embarrassed about. Almost all boys have them at some time during puberty.

If you ever have pain or a problem with your penis or testicles, it is important that someone take you to the doctor. It's best to get problems like this checked out.