Dossier: Family

What you need to know about puberty

Suddenly they’re there: pimples, moustache fuzz or breasts – puberty has arrived! But it’s not just the body that changes during this time. New feelings also throw family and friendships into turmoil. Discover all about this exciting phase of life.

Text: Katharina Rilling; photo: iStock

What typically happens during puberty?

Puberty is a time of radical reorganisation: the body and psyche change more drastically in this phase of life than in any other. Arguments with parents, melancholy, the first overwhelming crushes and a completely new body image – most people have to go through this when growing up. It’s an exciting and intense time – and also extremely stressful for everyone involved. But why is this? What happens to the body when we grow up? Here are the most important facts on the subject.

Why do we go through puberty?

During puberty, girls turn into women and boys into men. Incidentally, the term comes from Latin and means “manhood”. This means that a person matures from a child to an adult over a number of years. The biological goal is to become sexually mature and capable of procreating in order to produce children. 

A springboard to sexuality: When does puberty begin? And when is it over?

The exact age that children reach puberty depends on various factors – such as their disposition, their diet and their overall health. Normally, the first physical changes in girls in this part of the world begin at around 9 to 10 years of age and end at 16 to 18 years of age. The psyche often needs one, two or three years longer to adapt. Boys are known to be a little later: their bodies begin to change at around 10 to 14 years of age. The physical process is then complete at around 17 or 19. But beware: the figures vary greatly depending on the source and are only rough guidelines. The speed of development varies from person to person.

The onset of puberty probably also depends on body weight and fat content, among other things. There seems to be a threshold at which certain processes in the body, such as hormonal changes, are triggered. For example, girls with a higher body mass index (BMI) tend to menstruate earlier than their very thin peers, and their breasts also start to grow earlier.

Origin also plays a role. Puberty tends to begin earlier in African-American and Hispanic women than in Asian and white women. Studies also show that the time of the first menstrual period in Europe has shifted further and further forward since the 19th century: from the original 17 years (1850) to the current 12.5 years (since the 1960s). The first ejaculation also occurs earlier in young men today. Experts believe that this is due to more robust health among the population, a more balanced diet and better hygiene. However, hormone-active substances such as plasticisers and pesticides, which are ingested in small quantities from the environment, may also have contributed to this.

How do hormones affect puberty?

Everything starts in the head – or, to be more precise, in the hypothalamus. Why this thumbnail-sized area of the brain suddenly starts sending signals or hormones at a certain point to stimulate the production of sex hormones in the body is not yet fully understood. However, from this point onwards, it is mainly testosterone that is produced in boys and oestrogen and progesterone in girls. In turn, the increase in sex hormones gradually causes visible and invisible changes in the body.

Maturing too early – puberty during kindergarten? 

Some children develop breasts, body odour and experience emotional ups and downs as early as kindergarten or first grade. This might not sound tragic at first, but if the growth spurt starts before the age of eight for girls and before the age of nine for boys, it ends too early – and the children may never reach their normal size. What’s more, it’s emotionally stressful for a girl to have the body of a woman when her head is still half-buried in the sandpit. Parents should seek early advice from a doctor to find out whether hormone therapy is an option to delay puberty for a while. In most cases, it’s not possible to identify the cause of the early onset of puberty. 

What if puberty doesn’t want to start?

It’s also common for puberty to bide its time. If girls show no signs of physical change beyond their 14th birthday and boys beyond their 16th birthday, this is referred to as delayed puberty. This occurs slightly more often in boys than in girls. Parents should seek advice if development virtually stops or stops again for more than 18 months after it starts. It’s also atypical if a girl’s period does not start within five years of developing breasts. 

The process: the three phases of puberty in boys and girls

There is a defined sequence to sexual development, which can roughly be divided into three phases that merge into one another and overlap. Exactly how quickly this happens, and when, varies. 


As the primary school years slowly come to an end, the brain begins to produce more and more sex hormones, thus initiating the process of puberty. This first phase lasts around one to three years. It’s a time of physical development, but the psyche also begins to slowly undergo change. Some teenagers prefer to stay in their room, while others start to pick fights and rebel against their parents’ rules and boundaries.

Chest growth

In girls, what began as a small bulge under the nipple now develops into the female breast. This growth can be itchy or painful. Incidentally, it’s completely normal for one breast to grow faster than the other. What’s less well known is that the hormonal change can also cause boys to have temporarily larger and slightly painful breasts.

Pubic and underarm hair sprout

During puberty, the first pubic hair begins to grow. The hair slowly spreads in the genital area, becoming firmer and curlier. This development is complete in girls at around the age of 14. Hair also starts to grow in the armpits, albeit a little later: at around 12 to 14 years of age. Boys also develop facial hair. By the age of around 17, the hair is similar to that of an adult man. Incidentally, some men never develop chest hair, while others only grow it between the ages of 20 and 30.

Growth spurt

Adolescents suddenly go through the famous growth spurt, during which they shoot up by around 5 to 8 centimetres in a single year. This can lead to growing pains. Their physical proportions also gradually change and become more masculine (muscle mass and shoulder width increase) or feminine (body shape becomes more rounded at the hips and bottom, for example). Young adults should have reached their final body length by the age of 21.

Testicles and penis grow

At the age of 11 or earlier, boys’ testicles begin to grow and testosterone levels rise. The scrotum becomes more wrinkled and takes on a darker colour. The size of the penis also changes in boys. By the age of 19 at the latest, it is fully grown and stays that way. Testosterone can lead to sudden and unwanted erections, which is unpleasant for many.

High puberty

The most intense and often stressful phase of puberty usually takes place between the ages of 12 and 16. This is when the brain matures. Adolescents learn to control their impulses, realistically evaluate impressions, keep their emotions in check and assess the consequences of their actions. But their physical development does not stand still either. 

The female sexual organs develop

The ovaries and uterus grow unnoticed inside the female body. What is noticeably different, however, is that the inner labia and the entrance to the vagina become stronger and moist. The vagina and clitoris also grow, become more robust and get ready for sexual intercourse. Discharge now ensures that the vagina cleanses itself. Before the first period, this discharge is often whitish in colour. The vaginal flora changes and is now colonised by bacteria that fight foreign germs and keep the vagina healthy.

First period and sexual maturity

The first menstrual period is technically known as “menarche”. Bleeding can be irregular in the first few years and eventually settles into a regular rhythm. More and more eggs grow in the ovaries and ovulation occurs once a month. Girls are now sexually mature and can become pregnant. If they want to have sex with a boy, they need to think about contraception.

Voice change in boys

Speaking and singing now become a challenge: as the larynx and vocal cords grow, the voice becomes deeper. The child’s voice becomes an adult voice. Incidentally, girls’ voices also become deeper, namely by about three tones, while boys’ lower by an octave.

First ejaculation and sexual maturity

The first ejaculation usually already contains sperm. Secretions are now formed that give the sperm motility and the ability to survive. A woman can already be impregnated at this stage. However, the first ejaculation is usually triggered without sex – during sleep, through sexual fantasies or through touch.  

Body odour and skin change

Many young people suddenly no longer like their appearance or their scent. They cover themselves in deodorant, perfume and make-up. The reason: the sweat glands have set to work. If bacteria appears, a strong odour develops under the armpits. The odour of the genitals also changes. Physical hygiene becomes more important and not only hair but also blackheads and pimples sprout on the face, chest and back. Sebaceous glands now produce more sebum, the skin becomes more oily and the glands can become blocked and inflamed. Although puberty acne is usually only a temporary phenomenon, it affects many teenagers, can be very distressing and should definitely be treated by a doctor to prevent scarring.   

Rollercoaster of emotions

Bouts of sadness now alternate with feelings of joy and irritability or even outbursts of rage – all seemingly without reason. Risky behaviour, identity crises, unpredictability and rebellion against parents, teachers and the establishment can make teenagers difficult to live with. On top of all this, they’re dealing with their own insecurity, their first romantic feelings and a strong sexual desire.

Late puberty: welcome to adult life!

From around the age of 16, teenagers enter the final phase of puberty and their growth phases are now complete. Psychological developments now take place and, thankfully, family life becomes calmer and more harmonious again. The young adults have slowly separated themselves from their parents, become more self-confident and feel increasingly comfortable in their new skin. Fortunately, because this is the time when important decisions are often made, such as which career to pursue. Some people refer to this phase between puberty and adulthood as “adolescence” or “post-puberty”.

Parents and pubescent children

What can parents do? There aren’t many options. Showing a lot of understanding, giving them space and knowing that it will all pass are particularly important for parents at this time. Nevertheless, truancy, eating disorders, theft, substance abuse, depression and crime are particularly common during this phase. Families who are affected should seek professional help from a family counsellor, a doctor or a youth psychologist as soon as possible.

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