Puberty

Our bodies are constantly changing from the day we are born until the day we die. Puberty is the period of time when children begin to mature biologically. Girls start to grow into women and boys into men. This process can take a year or even six years. This time period is when a child's body takes on those characteristics that define it sexually. Both males & females bodies will each take on a different shape. Keep in mind that everyone matures at their own pace, but eventually we all catch up. Puberty leads to adolescence. Adolescence can be a very difficult time. You are no longer a child, but you are not an adult yet either.

During puberty, some changes happen only to girls, and some happen only to boys. What kinds of changes can you expect if you're a girl?

For one thing, your breasts will begin to grow and get fuller - so you may need to start wearing a bra, especially if you're active in sports. Often one breast grows faster than the other. Some girls' breasts grow more quickly than other girls' - and some girls' breasts remain small throughout their adult lives. Also during puberty, your hips will get rounder, and your waist will get narrower. Some girls begin shaving their legs or under their armpits.

Puberty also means that you will soon begin menstruating or having your period - one of the most significant changes a girl goes through during puberty. What happens during this cycle?

Girls have two ovaries. Each one holds thousands of tiny eggs. About once a month, an ovary releases one egg. This is called ovulation. The egg moves through one of two Fallopian tubes toward the uterus.

Before the egg is let go, the uterus begins building up a lining made of tissue and blood, which becomes like a nest for the egg if pregnancy happens. Usually, the egg breaks apart before it gets to the uterus. But if a sperm from a boy's or man's penis meets the egg on its way to the uterus, it can fertilize the egg. Pregnancy begins if a fertilized egg attaches itself to the lining of the uterus. When the egg breaks apart, the lining of tissue and blood isn't needed. It flows out of the uterus, through the cervix, through the vagina, and out of the body. This is called menstrual flow. To keep the menstrual flow from getting on your clothes, you will want to use sanitary napkins or tampons.

Some girls and women have their period only a few times a year. If you are sexually active and skip your period for a month, you should consult your clinician right away. You should also make an appointment if you are not sexually active but skip a period for three months in a row.

During puberty, some changes happen only to girls, and some happen only to boys. What kinds of changes can you expect if you're a boy?

Keep checking the mirror - once your voice has changed, you'll probably start growing a beard. Beards grow very slowly for the first couple of years, so the hair will be light at first and grow heavier as you get older.

During this time, your penis will begin to grow larger, and your testicles will get bigger and hang lower. Usually, one hangs lower than the other. Testicles are very sensitive, which is why it is important to wear protective cups or jock straps when you're playing contact sports. You may wonder how large your penis will end up being. Soft adult penises are usually between 3 1/4 and 4 1/4 inches long. Most hard adult penises vary from five to seven inches long, but some may be shorter or longer.

With the onset of puberty, you'll begin having erections more frequently. When you have an erection, your penis fills with blood and becomes hard. This usually happens when you are sexually excited, but it's also normal for you to sometimes get erections for no reason at all. These are called spontaneous erections. While they may make you feel embarrassed, spontaneous erections are perfectly normal. They usually go away after a few seconds or a few minutes on their own - and are probably not as noticeable to other people as they are to you!

Most boys your age have nocturnal emissions ("wet dreams"), where you get an erection and ejaculate in your sleep. You might wake up thinking you've wet the bed, but you haven't. The sticky liquid that comes out of your penis when you ejaculate is semen, not urine. Semen contains sperm, urine does not - and your body is made so that you cannot ejaculate and urinate at the same time. The semen that oozes out of the penis before ejaculation is called pre-ejaculate.

All of these changes - growing a beard, having wet dreams, and getting spontaneous erections -are completely normal, and are signs that you're growing from a boy into a man.

 source: http://www.plannedparenthood.org