Physical changes in girls
In girls, the physical changes that occur during puberty are usually marked by distinct stages of development. These stages are known as Tanner stages and were named after the child development expert, James Mourilyan Tanner, who first identified them.
As a guide, the Tanner stages give average dates of development. However, there can be a great deal of variation among different children and teenagers. Therefore, you should not worry if you reach a stage of puberty before or after your friends do.
The Tanner stages are described below.
Tanner stage one
Tanner stage one describes the changes that take place in your body before the onset of puberty. These are sometimes known as pre-pubertal changes. The changes usually occur between eight and 10 years of age.
During this stage, your body height will start to increase - by 5-6cm a year (2-2.4 inches) - your nipples may swell slightly and your ovaries will begin to grow.
Tanner stage two
Tanner stage two describes the onset of 'puberty proper'. It usually occurs at around 11 years of age. Your areola - the part of skin that surrounds the nipple - will begin to swell. Pubic hair will start to develop along the labia. The labia are the lips that are part of the external female sexual organs, known as the vulva.
The clitoris (a small, sensitive part of the female genitals which is part of the vulva) and the womb (uterus) will become larger during Tanner stage two.
The increase in body height will be 7-8cm a year (2.8 to 3.2 inches).
Tanner stage three
Tanner stage three usually occurs after the age of 12 years. The swelling of the areola, around your nipple, will continue, and you may have to buy your first bra. Your pubic hair will become coarser and curlier and you will begin to grow underarm hair.
These developments are usually followed by the appearance of spots (acne) on the face and back. Growth rate reaches its highest level with an average rise of 8cm a year (3.2 inches).
Tanner stage four
Tanner stage four usually occurs at the age of 13 years. Your breasts slowly develop into a more adult shape, with your nipple and areola swelling to produce a second mound that sits on top of the breast.
Although this may look slightly unusual compared to adult women's breasts, it is only temporary. The second mound will disappear once the rest of your breast develops.
During this stage of development, your pubic hair will start to look more adult-like in appearance, but it will not spread to your inner thigh.
Girls will usually experience their first period by Tanner stage four, and should be having regular periods by the end of the stage. During this stage, your growth rate will begin to slow down, with an average increase of 7cm a year (2.8 inches).
Tanner stage five
Tanner stage five is the final stage of puberty, and usually occurs when a girl is about 14-and-a-half years of age.
The swelling of your areola will disappear as the rest of your breast takes on a fully adult-like appearance. Your pubic hair should spread to your inner thigh and, by the end of the stage, you should have fully developed genitalia.
By around 16 years of age your growth rate should stop, by which time you should have reached physical maturity.
Physical changes in boys
The changes in a boy's development can also be classified using the Tanner stages. As with girls, dates of development should only be taken as an average because boys can also experience variations in age and development.
Tanner stage one
As with girls, Tanner stage one is usually regarded as pre-pubertal changes. Your adrenal gland (glands that start at the top of your kidneys) will stimulate an increase in your body height, usually 5-6cm a year (2-2.4 inches).
Tanner stage two
Tanner stage two usually begins at about 12 years of age. Your scrotum will begin to thin and redden, and your testicles will increase in size.
Some fine pubic hair will start to appear at the base of your penis. Your body fat usually decreases, while the increase in your body height will stay at the same rate of 5-6cm a year.
Tanner stage three
Tanner stage three usually begins after a boy has turned 13 years of age. Your penis will grow and lengthen, and your testicles will continue to grow.
Your pubic hair will become thicker and curlier, spreading to the soft mound of skin above your genitals (mons pubis). Your breasts should experience some mild swelling. This is perfectly normal and does not mean that you will grow a pair of 'man-boobs'.
Your may begin to experience 'wet dreams' which are involuntary ejaculations of semen ('come') during your sleep. This can be embarrassing but it is perfectly normal and it is not your fault. If you want to prevent 'wet dreams' from soiling your bed clothes, wearing a pair of underpants while sleeping may help.
During Tanner stage three, your voice should 'break'. You may find that the pitch and tone of your voice suddenly changes for short periods of time. The size of your muscles will increase, and your growth rate will also increase; usually to between 7-8cm a year (2.8 to 3.2 inches).
Tanner stage four
Tanner stage four usually begins at around 14 years of age. Your penis and testicles will continue to grow, and your scrotum will take on a darker appearance. Your pubic hair will appear more adult-like, but will have not spread to your inner thighs.
You should begin to start growing underarm hair, your voice will change permanently, and you may develop acne.
Tanner stage five
As with girls, Tanner stage five is the final stage of puberty, and it usually starts at about 15 years of age. Your genitals will take on a fully adult-appearance and pubic hair will spread to the inner thigh. You will also begin to grow facial hair, and may have to begin shaving.
Your growth rate should start to slow down, and will finally end at around 17 years of age. However, after this age, you may still experience a further increase in muscle size. Most boys will reach full adult maturity between 18 and 19 years of age.
Acne
During puberty, your body becomes more sensitive to the hormone testosterone, which is present in both boys and girls. The testosterone cause small glands in your skin to produce too much oil (sebum).
Dead skin can also block the opening of hair follicles (the small tubes in your skin that hold a hair in place). The sebum can build up behind the blocked follicle, which can cause blackheads, or whiteheads, to develop.
Hormonal changes will also alter the levels of acid in your skin, encouraging the growth of bacteria. The bacteria can also infect a blocked hair follicle, producing a deeper infection, such as a spot (pustule) or a nodule.
Mild to moderate acne can usually be successfully treated using an antibacterial cream. However, if your acne is more severe, you should see your GP who may recommend antibiotic tablets (oral antibiotics).
Body odour
During puberty, your body begins to develop large sweat glands around your armpits, breasts and genitals. These are known as apocrine glands. Apocrine glands release sweat in response to stress, emotion and sexual excitement. In some cases, the excess sweat can cause body odour.
However, washing twice a day and using deodorant should help to control body odour.
Periods
A girl's periods usually start some time between 8 and 16 years of age. However, they will most commonly start at 12-13 years of age. Your periods will continue until the menopause, which usually occurs at 45-55 years of age.
In the days leading up to your period, you may experience a number of symptoms. These may include:
- sore breasts,
- irritability,
- backaches
- spots, and
- feeling very emotional, or upset.
These symptoms should pass once your period starts. Many girls and women experience pain or cramping in their abdomen, back and vagina. This is often referred to as period pains. Taking paracetamol may help to relieve period pains.
