Hair, Everywhere

Soft hair starts to grow in the pubic area (the area between the legs and around the genitals [the vagina or penis]). This hair becomes thick and very curly. It is not necessary to shave your pubic hair. You may also notice hair under your arms and on your legs. Boys start to get hair on their face or chest. Some girls notice that the hair on their legs has become darker. You may choose to shave or trim unwanted hair.

Acne

During puberty, your skin gets oilier. This oil can cause acne (also called pimples or zits). Acne is not caused by dirt or certain foods, and you can't catch acne from another person or give it to them. Talk with your doctor or other health care provider about how to treat and control acne. Here are a few skin care tips.

• Do wash your face twice a day. In general, milder soaps and cleansers are better for your skin.

• Do use an oil-free moisturizer on your face after washing.

• Don't pop or pinch your zits. All this does is break open the lining of the oil ducts and make them redder and more swollen. This can also cause scars.

• Don't scrub your skin too hard. This irritates the skin.

Body Odor

You may begin to sweat more. Most people use a deodorant or an antiperspirant to control underarm odor and wetness.

Other Changes (Girls)

Breasts. In most girls, the first sign of puberty is breast development (small, tender lumps under one or both nipples). There may be soreness, which goes away as your breasts grow. Don't worry if one breast grows a little faster than the other. By the time your breasts are fully developed, they usually end up being the same size. When your breasts get larger, you may want to start wearing a tank top or bra under clothing. Some girls are excited about this. Other girls may feel embarrassed, especially if they are the first of their friends to have breasts. Talk with a parent or another trusted adult to work through your feelings and get advice on tank tops and bras.

Shape. As you go through puberty, you get taller, your hips get wider, and your body begins to build up fat in your belly, hips, thighs, buttocks, and legs. It is normal for girls to develop different body shapes.

Periods. Your menstrual cycle, or "period," starts during puberty. Most girls get their periods 2 to 2½ years after their breasts start to grow (between 10 and 15 years old). After the first period, it can take up to 2 years for periods to occur every month. When you start having periods, you are able to get pregnant—even if you don't have a period every month.

During puberty, your ovaries begin to release eggs. A baby may develop in your uterus if an egg connects with sperm during sexual intercourse. To help your body prepare for this, a thick layer of tissue and blood cells builds up in your uterus. If the egg doesn't connect with sperm, your body does not need these tissues and cells. They turn into a bloodlike fluid and flow out of your vagina. Your period is the monthly discharge of this fluid out of your body.

During your period, wearing a menstrual pad, menstrual cup, or tampon or wearing menstrual underwear protects your clothes. These can be used together and need to be changed every few hours. Most periods last from 3 to 7 days. You may find it helpful to track your periods on a calendar or smartphone app.

Having your period does not mean you have to avoid physical activities like swimming, running, or physical education class. Exercise can even help get rid of cramps and other discomforts you may feel during your period.

Other Changes (Boys)

Height. Around 13 to 15 years old, you will have a growth spurt, meaning a large growth in height and shoe size. During this time, you may feel hungrier and eat more. Because you are growing quickly, you won't be very muscular until the growth spurt stops.

Muscles. As you go through puberty, you get taller, your shoulders get broader, and, as your muscles get bigger, your weight increases. These changes usually occur later in puberty, around 15 to 18 years old.

Penis and testes. During puberty, the penis and testes get larger. There's also an increase in sex hormones. You may notice that you get erections (when the penis gets stiff and hard) more often than before. This is normal. Even though you may feel embarrassed, try to remember that unless you draw attention to your erection, most people won't notice it. Also, everyone's penis is different, so if the size of yours differs from that of another person's, it doesn't mean there is anything wrong with you.

Wet dreams. During puberty, your testes begin to produce sperm. So during an erection, you may also ejaculate. Ejaculation is when semen (made up of sperm and other fluids) is released through the penis. This could happen while you are sleeping. You might wake up to find that your sheets or clothes are wet. This is called a nocturnal emission, or "wet dream." This is normal and stops as you get older. Once this starts happening, it is possible to get someone pregnant if you have sex.

Voice cracking. Your voice gets deeper, but it doesn't happen all at once. It usually starts with your voice cracking. As you keep growing, the cracking stops and your voice stays at the lower range.

Breasts? You may have swelling under your nipples. If this happens to you, you may worry that you're growing breasts. Don't worry, you're not. This swelling is very common and only temporary. Most common ages for male breasts are 11 to 16 years. But if you're worried, talk with your doctor.

Deciding to Wait

If you decide to wait, plan how you are going to say no so you are clearly understood. Stay away from situations that can lead to sex. For example, avoid being alone with someone who has been pressuring you to have sex. Or avoid using drugs or alcohol or going to party where people are using drugs or alcohol. Remember, a person who doesn't support your decision to wait may not be the right person for you.

Making Health Decisions About Sex

If you decide to have sex, it's important that you know the facts about birth control, sexually transmitted infections (STIs), and emotions. Sex increases your chances of becoming pregnant, becoming a teen parent, and getting an STI, and it may affect how you feel about yourself or how others feel about you. These are important decisions and are worth talking about with adults who care about you, including your doctor.