transition from a sexually immature child to a sexually mature adult From Wikipedia, the free encyclopedia
Puberty is what happens in children's bodies that changes them into adults. Puberty, depending on sexes, usually takes about four or five years maximum. However, when most people say "going through puberty", they usually just mean approximately the first two years. After that, people sometimes use the word adolescence, although that is a not a very precise word. As girls and boys go through puberty, they become able to have sexual intercourse (sex) and produce children of their own. A girl can become pregnant and have a baby. During puberty, a boy's body begins making semen, and he starts to be able to ejaculate, which is semen shooting out from his penis when he is sexually excited. If he has sex with a girl, meaning he puts his penis into her vagina and ejaculates in her, he can make her pregnant.
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There are also changes that happen in the brain. Boys and girls may think about sex more. While children of any age explore, touch and play with their sex organs from time to time, all boys and most girls going through puberty do this a lot. This is called masturbation and is a totally normal and healthy thing to do. Boys and girls going through puberty may question their sexual orientation, meaning they find they are more attracted to the people of the opposite sex, or to people of their own sex, or to both, or their sexual feelings may be fluid (changing) and complicated, often called being queer. People going through puberty often have strong emotions or feelings about many things. Other changes in the brain may make it harder learn a new language the way they learned language(s) when they were young. This change involves something called brain plasticity. It means that children's brains are more flexible in learning.
Puberty is started by hormones, which are chemicals that tell parts of the body to do things. For reasons which are not completely understood, girls and boys now start puberty when they are younger than it happened to boys and girls in the past. Some girls now start puberty at age 9 or 10 or even earlier. For boys puberty is also happening earlier. A 2012 study[1] found that, on average, African American (Black American) boys begin puberty at age 9 while white and Hispanic boys start at age 10, on average. People around the world start puberty at different ages. The reasons for girls and boys starting puberty earlier might be that they eat healthier food and drink more milk. Other reasons might be chemicals in food, chemicals in plastic containers, chemicals in the air and chemicals in the water. The reasons are not known for sure.
Puberty happening too early is called precocious puberty. This can create problems for the child. Sometimes a young person's body is wrong for what gender they feel they are. They feel there was a mix-up. In both these situations, drugs called puberty blockers can slow down or temporarily stop the process of puberty.
Changes that happen to boys and girls during puberty include the sex organs growing bigger, hair appearing on the body, and growing taller and stronger. These changes are called secondary sex characteristics. People often notice boys' voices getting deeper, and girls growing breasts and starting to menstruate (have periods).
Because puberty is the time in a child's life when he or she becomes able to make children, this is seen as very important. Therefore, people in many countries around the world have different ways of marking this event.
Puberty is started and carried on by different hormones. Hormones are chemicals that tell parts of the body to do things. Hormones are made by glands in the body. Glands are organs (special parts) of the body that make hormones.
This is what happens during puberty:[2]
On average, girls begin puberty at ages 10–11; boys it's unclear the average age due to the rise of early puberty (according to the 2012 study[4] found African American boys starting to develop on average at age 9 while White and Hispanic at age 10)[5] The experts who did this 2012 study said puberty starts in boys when Tanner stage 2 pubic hair is seen.[6] Stage 2 pubic hair means a small amount of long downy (soft or fine) hair, with color, which is straight or only slightly curled. The hair is seen chiefly at the base of penis.[7] In the past, it was said that for girls, puberty begins around 10 or 11 years of age and ends around age 16. Boys enter puberty later than girls. In the past, it was said that boys usually start puberty around 12 years of age and it lasts until around age 16 or 17."[8] Girls usually complete puberty by ages 15–17,[9][10] while boys usually complete puberty by ages 16–17. The major landmark of puberty for females is menarche, the onset of menstruation, which occurs on average between ages 12–13;[11][12][13] for males, it is the first ejaculation, which occurs on average at age 13.[14] If puberty starts much later than average, the person is sometimes called a late bloomer.
For most boys, puberty takes about a few years, for White and Hispanic tend to start puberty about a year later than African American boys so you may not finish puberty until you're older. For African American boys it's normal to finish puberty a bit sooner.[15] Teenagers are usually about 10 to 30 centimetres (cm) (4 to 12 inches (in)) taller, 7 to 29 kilograms (kg) (15 to 65 pounds (lb)) heavier, and stronger. He is also able to make a woman pregnant (have a baby).[16]
In rich countries in the 21st century, the average age at which children, especially girls, reach puberty is lower compared to the 19th century, when it was 15 for girls and 16 for boys.[17] This can be due to improved nutrition resulting in rapid body growth, increased weight and fat deposition,[18] or eating meat from animals which have been dosed up with estrogen.[19][20]
This is the general picture, but people around the world may start puberty at different ages. This is because their environment (things around them) may differ quite a bit.[21] Here are some of the things that make puberty happen at different ages in people:
Girls usually reach their adult height and become sexually mature (able to have babies) about four years after puberty starts. Boys keep growing for about six years after puberty starts. Puberty in boys starts off more slowly than in girls, but then speeds up later on. Although boys are usually about 2 centimetres (0.8 in) shorter than girls before puberty begins, men on average end up about 13 centimetres (5.1 in) taller than women.[28]
The first sign of puberty in boys is that their testicles (also called the testes) and scrotum (the "bag" that the testicles are in) grow bigger.[29] Before puberty, each testicle is about 1.5 to 2 cm (0.6 to 0.8 in) long and a volume of about 2 to 3 cubic centimetres (cc) (0.1 to 0.2 cubic inches (cu in)). About six years after puberty starts, the testicles reach their adult size.[30] The volume of an average adult man's testicle is about 18 to 20 cc (1.1 to 1.2 cu in). However, it is normal for some men to have testicles smaller than this size, and for other men to have larger testicles.[31]
The penis also grows bigger during puberty. At the start of puberty, the average length of the penis is 6 cm (2.4 in). The penis reaches adult size about five years later.[32] A study done in 1996 found the mean length of an adult man's penis is 3.5 in (8.9 cm) when it is flaccid (pronounced [ˈflæsɪd], FLA-sid) (not erect or hard).[33] The average length of an erect penis is about 12.9 to 15 cm (5.1 to 5.9 in).[33][34]
The testicles have two main jobs: to make hormones and sperm. The testicles make the hormone testosterone, which spreads around the body. This causes the changes in the body that make a boy grow into a man. Testosterone also makes a man feel like having sex. One year after puberty begins, when boys urinate (pee) after waking up in the morning, some sperm can be found in the urine. When a boy is about 13 years old his testicles will have grown to the stage that he may be fertile (able to make a woman pregnant). However, it will still be difficult for him to do so. Boys usually only become fully fertile when they reach about 14 to 16 years of age. The sperm in the testicles mixes with other liquids in the body to form a whitish or yellowish and sticky fluid called semen. During puberty, two glands in the body called the seminal vesicles and prostate also grow bigger.[35] These glands make a lot of the liquid that is in semen.
When a man is sexually excited, he gets an erection – his penis becomes bigger, longer, and harder. A male can become sexually excited if thinks about sex or sees a good-looking person, or if his penis rubs against something. During puberty, some boys also have spontaneous erections. These are erections that happen by themselves without any reason. This can be embarrassing when it happens in a public place.[36]
When a man's penis is sexually stimulated for some time, he has an orgasm and semen shoots out from the penis. This is called ejaculation. Boys who have not begun puberty cannot ejaculate. A boy's first ejaculation usually happens about one year after he begins puberty. For some boys, the first ejaculation takes place when they are sleeping. This is called a nocturnal emission or a wet dream. It happens without the boy's control, often when he is having a dream about sex. Scientists believe that wet dreams are the body's way of removing too much semen. A study was done of 5,300 white men in the United States in 1948[37] found that 13% of them had their first ejaculation through a wet dream,[38] This seems to tell us that most boys have their first ejaculation after masturbating. A male masturbates when he rubs his penis to make himself feel good sexually. The study also found that most boys who have their first ejaculation by masturbating do this a year or more earlier than boys who have their first ejaculation through a wet dream.[39] A 2004 survey by a magazine in Canada found that most males (43%) started masturbating when they were about 12 to 13 years old.[40] When a boy begins masturbating, wet dreams often stop happening because semen is taken out from his body regularly.
When a boy starts to ejaculate, he usually produces only a small amount of semen. The semen is different from what an adult man produces. It is usually clear and stays sticky. It either has no sperm in it, or sperm that do not move properly or do not move at all. A boy's semen only becomes like an adult man's semen about two years after his first ejaculation.[41]
Not long after a boy's testicles and penis start to grow, pubic hair (pronounced [ˈpjuːbik], PEW-bik) begins to appear. Pubic hair is hair that grows in the pubic region, which is the part of the body where the penis is. Pubic hair is shorter, curlier, and rougher than hair on the head. It usually starts growing on the abdomen above the penis at the place where it joins the body. (The abdomen is the part of the torso where the navel or bellybutton is.) There may also be some hair on the scrotum. After about six months to a year, there will be a large triangle of hair in the pubic region. Within three to four years after puberty begins, there is a lot of pubic hair in the area above the penis. Later on, pubic hair also grows on the abdomen upwards towards the navel and on the insides of the thighs.[42]
About two years after pubic hair starts to appear,[42] hair also grows on other parts of the body:
The hair on the arms, legs, chest, abdomen, and back may also become thicker. Different men have different amounts of body hair. Many boys begin shaving when hair starts growing on their faces.
A larger amount of male hormones in the body cause changes in perspiration (sweat). This gives it a more "adult" body odor or smell. The hormones also cause sebaceous glands in the skin to make more sebum, a type of oil that keeps the skin from getting too dry. Sebum and dead skin cells can mix with a type of germ called bacteria and block pores (tiny openings) in the skin. This causes a skin problem called acne. Most people get acne during puberty. When a person has acne, he gets swellings on his skin called blackheads, whiteheads, and pimples. Blackheads and whiteheads are painless, but pimples can be red and painful. They usually form on the face but can also appear on the neck, shoulders, upper back, and chest. Oil glands on scalp – the part of the head on which hair grows – also make a lot of sebum. This can cause dandruff, in which small white bits of skin fall from the scalp.[43]
During puberty, a boy's larynx or voicebox also grows larger. This makes the laryngeal prominence or Adam's apple – the lump that sticks out of the front of his neck – larger too. As the larynx grows the vocal folds become longer and thicker, so they vibrate (move back and forth) more slowly. This causes the voice to lower in pitch or tone and become deeper. When this happens, it is sometimes said that the boy's voice has "broken". However, it actually does not happen overnight but over some time. During this time, the voice may sound scratchy. On average, a boy's voice normally reaches its adult sound when he is around 15 years old.[44]
Towards the end of puberty, boys go through a "growth spurt" which lasts for about two to three years. During this time, their body grows taller very quickly. When the growth spurt is at its fastest point, some people grow 10 cm (4 in) or more a year. This happens about two years after puberty starts, usually between the ages of 13 and 15. When a boy reaches the end of his growth spurt when he is about 18 years old, he will be at his adult height. His body will not grow much taller after that.[2][45] Because of their growth spurt, boys' muscles can feel sore. These "growing pains" can feel worse if boys are active and do a lot of exercise. They go away after a while.
Boys grow more slowly than girls but for a longer time. That is why most men are taller than women.[45] By the end of puberty, adult males have heavier bones and more muscle than females. In an average adult man, muscle makes up 50% and fat 15% of his weight. On the other hand, 40% of an average adult woman's weight is made up of muscle while 27% is made up of fat. Because men have less body fat than women, their hips generally do not grow bigger. Some bones like those in the jaw and shoulders grow more in males than in females. That is why males have wider faces and shoulders but narrower hips.[46]
The changes in a girl's body during puberty usually take place between the ages of eight and 18 years. Most girls will have finished puberty around the age of 15. They will have breasts and pubic hair, will menstruate (have a period) every month, and will be able to get pregnant. They will usually also have reached their full adult height.[47]
When the breasts start to grow, this is normally the first sign of puberty that can be seen on the outside of a girl's body. This usually happens when girls are about the age of 10.5 years. A lump that is a bit hard appears in each breast under the areola, which is the dark ring around the nipple. The lump in one breast may grow before the other one.[48] This is called breast budding.[49] Within six to 12 months, both breasts will have started growing. The swelling can be felt and seen outside the edges of the areolae. About one and a half to two years after the breasts first start growing, they are close to the shape and size of an adult woman's breasts. The nipple and areola may be on a smaller mound on each breast. This small mound usually goes away when each breast is fully grown.[50] Whether the breasts are small or large depends on how much fat there is in the body.[49][51]
Between the ages of about eight and 14 (on average, at 11 or 12 years), pubic hair begins to grow along the labia (the "lips" of the vulva), usually a few months after the breasts start growing.[50][52] At first the hair is thin and straight instead of curly, and there is not much of it.[47][52] Within a year, the pubic hair becomes rough, dark, and curly and grows in a triangle shape in the pubic region. About one year after pubic hair begins appearing, underarm hair also grows. The hair on the arms and legs also gets thicker, and some girls may have hair appearing on their upper lip and in front of their ears.[53]
Like boys, higher amounts of hormones in the body cause girls' perspiration (sweat) to change. This gives them a more adult body odor or smell. The hormones also cause the skin to produce more sebum (oil), which usually leads to acne.
When girls are between eight and 11 years old, the two ovaries in their bodies begin to grow bigger.[47] Each ovary is egg-shaped and is attached to the side wall of the pelvis. The pelvis is a large set of bones in the hips. The ovaries are organs that make female hormones. These hormones cause a girl to grow into a woman, and make her feel like a woman. The hormones also make it possible for females to become pregnant and have babies. Inside the ovaries are about 200,000 ova (egg cells).[54] For a baby to be formed, a woman's ovum and a man's sperm must come together. During puberty, the ova also grow bigger.[55]
Between the ages of nine and 15 years (on average, at 12 to 13 years), the vagina and uterus (womb) become bigger.[47][55] The uterus is the organ in which a baby grows. The vagina is a tube leading from the uterus to the outside of the body. The opening of the vagina is inside the vulva, in between the legs. A clear or whitish fluid may start to flow out of the vagina to keep it clean.[48] Then, about two years after the breasts start to grow,[56] when a girl is between ten and 16 years old (on average, at 13 to 14 years), hormones made by her ovaries cause the ovaries to release an ovum, which moves into the uterus. Usually, only one ovum is released at a time. The hormones also tell the uterus to get ready for a baby, in case the ovum meets a sperm cell and gets fertilized. The walls of the uterus become thicker with extra tissue. Inside the thick part of the uterus are blood vessels and other nutrients that a baby will need to grow. If an ovum in the uterus gets fertilized, it sticks to the wall of the uterus and starts to grow. However, if the ovum is not fertilized, it does not stick. The uterus then gets rid of the ovum and the extra tissue by releasing it from the body. The tissue and blood flows out of the uterus through the vagina. This is called menstruation or having a period. The bleeding normally lasts for about three to five days, though some girls may bleed for longer or have a bit of bleeding between periods.[57] The uterus then starts preparing for another ovum. For most girls, the time between their periods is about one month. For about two years after menstruation starts, the time between periods is not always the same.[58] Some girls may skip a month, or have two periods close to each other. It is also normal to have cramps (rather painful squeezing feelings) or to feel bloated (swollen up) in the abdomen during periods.[57] When many girls start having periods, they begin using sanitary napkins (also called sanitary pads) or tampons to soak up the blood and tissue. A sanitary napkin is a piece of material that is absorbent (able to take in liquids) and is worn between the vulva and underpants. A tampon is a stick of absorbent material that is placed inside the vagina.
In 2004, a survey by a Canadian magazine found that most females (25%) started masturbating when they were about 12 to 13 years old.[40]
Because of more hormones in the body, girls start to have more fat in their breasts, abdomen, hips, and thighs. At the age of ten years, the average girl has 6% more body fat than the average boy, but by the end of puberty, the difference is nearly 50%.[59] The fat makes sure that a baby growing inside a pregnant woman will have enough nutrients. Also, the bones in the pelvis move further apart to make room for a larger uterus and ovaries, so there is space for a baby to grow in the uterus and to pass out of the body when it is born. The extra fat and wider hip bones that girls have give them a curvier shape.[60]
Girls also experience a growth spurt during puberty. In the first year after puberty begins, they grow about 8 cm (3 in). They grow even faster the next year or so, then the growth slows down and almost stops when they start menstruating. After a girl's periods begin, she usually does not grow more than 5 cm (2 in) taller.[53]
The large amounts of hormones in the bodies of boys and girls during puberty can also affect their emotions. Young people begin to be attracted by (drawn to) each other and thinking about what it is like to have sex. They are often worried about what other people think about them. They can also feel the urge to do things that are dangerous, such as taking drugs or too many alcoholic drinks, or smoking. They sometimes want more independence – more power to decide things for themselves – and can get angry when their parents do not allow them to do things. The brains of teenagers are still growing, and it may take a while before they are mature enough to know how to make good choices about their lives. Therefore, it may be helpful for them to follow the advice of adults they trust, even if it does not make much sense to them at the time.[61]
This is a very controversial and debated topic, but sometimes, whether due to external influences or not, a person's body is wrong for their perceived gender identity. They may have male sex organs but feel that they are a female, or they may have female sex organs but identify as male. Medical operations by doctors and hormone pills can change the body, but those operations are not done on young people. Instead, doctors can give drugs that slow down or stop puberty so the person has more time to decide what to do. As of 2023, some states in the United States say doctors cannot give these drugs to young people. The talk about these drugs has become very political. These drugs were usually made for other reasons, such as stopping cancer. These drugs can also be used if a child starts puberty at a very early age, such as 7 or 8. The name for that situation is "precocious puberty." Going through puberty too early creates medical and psychological problems. The person might not grow as tall as they could. They might feel very different from their friends and other children in school. Girls who go through puberty early have a bigger chance of being sexually assaulted. They also have a bigger chance of becoming pregnant while still a young teenager. There might be a bigger chance that later in life they might get a cancer such as breast cancer, because there is a higher risk associated with the number of years in between when the woman went through puberty (usually defined as menarche for studies) and the first time she has a baby. Studies have shown that early-maturing boys are more likely to be sexually active and are more likely to participate in risky behaviors.[62] One of the drugs that can be given to people with boy bodies is called Lupron Depot. It works by causing a very big drop in testosterone levels. The drugs to block or slow puberty can be given with a needle in the leg, or sometimes the shoulder. In a young person with a boy body, for some drugs, the needle is put in a testicle. Sometimes the drugs are in a patch that is under the skin of an upper arm. The patch is usually changed once a year.[63] There is a chance that unwanted things could happen because of these drugs. These things are called side effects. There are some short term side effects, most of which are not huge problems for most people getting the drugs. The more important thing is that these drugs might have long-term effects on:
With drugs involving body chemicals called hormones that regulate things like growth, there might be a slight chance of increasing cancer risk, even though these drugs are often used as anticancer drugs.
Because puberty is the time in a child's life when he or she becomes able to make children, this is seen as very important. Therefore, people in many countries around the world practice Rites of passage to mark this change.