As children approach their early teens, puberty begins. These are the changes that will lead to adulthood, and the ability to have children.
The developments affect the body in terms of size, shape, and composition, as well as internal body systems and structure. Psychological and social changes also take place. Boys and girls grow rapidly in the first half of puberty, and they stop growing when puberty is completed.
Hormone signals from the brain will tell the body that it is time for puberty to start. The signals will go to the ovaries in females, and the testes in males.
In response, the ovaries and testes produce a range of hormones that stimulate growth and change in various parts of the body, including the reproductive organs, breasts, skin, muscles, bones, hair, and the brain.
Contents of this article:
Male and female hormones and puberty
Puberty differs in a number of ways between boys and girls. Girls start puberty about 1 to 2 years earlier than boys, and they generally finish more quickly.
Puberty can be an exciting and challenging time.
Girls reach adult height and are able to have children approximately 4 years after the first physical signs of puberty, but boys continue to grow for about 6 years after the first visible signs.
A girl's puberty can span from the age of 9 to 14 years, while a boy's lasts from the ages of 10 to 17 years.
The main male sex hormones are testosterone and androgen. Testosterone produces the changes related to virilization, or "becoming male," including a deeper voice, facial hair, and muscle development.
Female development depends mostly on estrogen and estradiol. Estradiol promotes the growth of the uterus and breasts.
Both males and females have estradiol, but levels rise earlier in girls than in boys, and women have higher levels than men. Similarly, testosterone plays a role in female development, but to a lesser extent than in males.
How does puberty affect females?
During puberty, the female sexual organs grow, and menstruation begins. After this, pregnancy can occur.
The first sign may be a vaginal discharge, and the appearance of body hair in the pubic area, under the arms, and on the legs.
Skin becomes more oily, and the body produces more sweat, making deodorant necessary. This is because the oil and sweat glands are developing. Acne is also common.
Changes appear in the shape and size of the body:
- The breasts start to grow, often starting with a small and sometimes painful lump just below the nipple
- The hips widen, the waist becomes proportionally smaller, and extra fat will develop on the stomach and buttocks
- The arms, legs, hands, and feet may grow faster than other parts of the body.
Some girls feel uncomfortable during this stage of development, but it is normal. The accumulation of extra fat is normal, and it does not necessarily mean that the girl is overweight.
Emotions may fluctuate, causing irritability, especially around the time of the monthly period. This is because hormone levels vary during the menstrual cycle.
If the emotional changes become too strong, a doctor may be able to provide medication or suggest lifestyle changes that can help, such as regular physical exercise to help reduce the effects of premenstrual tension (PMT) or premenstrual syndrome (PMS).
What happens to boys in puberty?
As boys enter puberty, the scrotum becomes thinner and redder, and the testicles start to grow. Around the age of 13 years, the penis grows and lengthens.
The voice box, or larynx, gets bigger, the muscles or vocal cords grow, and the voice will "break" or "crack," and eventually become deeper.
Boys grow in size and strength, and their social and emotional life changes too.
There may be "wet dreams," when the boy ejaculates while sleeping, and wakes up in the morning to find damp sheets and pajamas. Involuntary erections can also occur at this time.
These things happen automatically, usually without the penis being touched and without the boy having sexual thoughts or dreams. He cannot prevent it from happening: it is just part of growing up.
Breast enlargement is not unusual. Hormonal changes may cause a bump under one or both nipples that can feel tender, or even painful. Eventually, the swelling and pain will disappear.
The skin becomes more oily, and there will be more sweat, because the oil and sweat glands are growing. Deodorant may be needed. Acne is common.
Body size will change, and there will be growth spurts, peaking about 2 years after puberty begins.
The arms, legs, hands, and feet may grow faster than other parts of the body, making the boy may feel clumsy. Total body fat content will start to drop as muscle develops.
Body hair starts to grow around the pubic area, under the arms, and on the legs and arms, and facial hair appears around the upper lip and chin.
Facial hair can be shaved off. This can cause a rash, especially if the boy has sensitive skin, but shaving foam or gel may help to prevent rashes. Electric razors reduce the risk of cuts.
Emotions change, and there may be mood swings. One moment, the young man may feel like laughing, and then he may suddenly feel like crying. There may be intense feelings of anger.
This is partly because of the increased levels of hormones in the body, but also because it can be hard to come to terms with all the physical changes that are taking place.
Both boys and girls may need support at this time, for example, an older family member or a friend to talk to about the changes and how to manage them.
What happens if puberty is early?
Research suggests that puberty is starting earlier now.There are two types of early puberty, one of which may need medical attention.
Fast facts about puberty
- In the US, the average age of menstruation is 12.1 years for white girls and 12.6 years for black girls
- This age has fallen by a few months since 40 years ago, and from age 17 years a century ago
- In 50 percent of girls, breast development starts before age 10 years, and in 14 percent it starts before age 8 years.
In 2010, a study of 1,200 American girls found that 10.4 percent of white non-Hispanic girls had begun puberty at age 7, and 18.3 percent had started at 8 years, as measured by breast development.
The increase is significant compared with a similar study in 1997.
Common signs of early change are the premature appearance of pubic hair and body odor. Girls may see early breast development, but this is often fatty tissue, and the development is considered non-progressive.
Most of these are variations of normal growth and physical development. They are not considered a matter of concern, and no intervention is recommended.
This type of early puberty is thought to be a combination of genetics, environment, and individual factors, such as weight.
Precocious puberty, on the other hand, may indicate underlying problems.
Puberty may be considered precocious if it starts before the age of 7 to 8 years in girls and before 9 years in boys. Girls with progressive breast development over a 4- to 6-month period of observation, or boys with progressive penis and testicular enlargement, and rapid growth overall, may need medical attention.
Therapies may be necessary that will temporarily stop the effect of the hormones, especially if the imbalance could cause problems later in life, such as weak bones or lack of growth.
What if puberty is late?
If a girl has no signs of breast development by the age of 14 years, or no menstrual period by 16 years, or if a boy's testicles have not developed by the age of 14 years, they should see a physician.
Diabetes, kidney disease, or asthma may lead to late puberty, and genetic conditions such as androgen insensitivity syndrome (AIS) can affect it. AIS is when the body does not make use of some hormones.
Late puberty can normally be treated successfully, often with the use of hormone medications.
Puberty can be a challenging stage of development for young people, not only physically but also mentally and emotionally. Having the support of family members and friends is very important at this time.