When does puberty start? Puberty starts when changes in your child's brain cause sex hormones to start being released from the gonads, which are the ovaries and testes. This typically happens around 10-11 years for girls and around 11-12 years for boys.Skip
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What is puberty?
Puberty is the time when your child moves through a series of significant, natural and healthy changes. These physical, psychological and emotional changes are a sign that your child is moving from childhood towards adulthood.
Changes in puberty include:
physical growth and development inside and outside children’s bodies
changes to children’s sexual organs
brain changes
social and emotional changes.
When does puberty start?
Puberty starts when changes in your child’s brain cause sex hormones to start being released from the gonads, which are the ovaries and testes.
This typically happens around 10-11 years for girls and around 11-12 years for boys.
But it’s normal for the start of puberty to range from 8-13 years in girls and 9-14 years in boys.
There’s no way of knowing exactly when your child will start puberty. Early changes in your child’s brain and hormone levels can’t be seen from the outside, so it’s easy to think that puberty hasn’t started.
Puberty can be completed in about 18 months, or it can take up to 5 years. This range is also completely normal.
Girls: key physical changes in puberty
In girls, these are the main external physical changes in puberty that you can expect.
Around 10-11 years
Breasts will start developing. This is the first visible sign that puberty is starting. It’s normal for the left and right breasts to grow at different speeds. It’s also common for the breasts to be a bit tender as they develop. If your child wants a bra, a soft crop top or sports bra can be a good first choice.
A growth spurt occurs. Some parts of the body – like the head, face and hands – might grow faster than limbs and torso. This might result in your child looking out of proportion for a while. On average, girls grow 5-20 cm. They usually stop growing at around 16-17 years.
The body shape will change. For example, a girl’s hips will widen.
The external genitals (vulva) and pubic hair will start to grow. Pubic hair will get darker and thicker over time.
Around 12-14 years (about two years after breast development starts)
Hair will start growing under the arms.
A clear or white discharge from the vagina starts several months before periods start. If the discharge bothers your child, you could suggest your child uses a panty liner. If your child says it’s itchy, painful or smelly, consult your GP.
Periods will usually start within 2 years of breast growth starting, but can take up to 4 years.
Boys: key physical changes in puberty
In boys, these are the main external physical changes in puberty that you can expect.
Around 11-12 years
The external genitals (penis, testes and scrotum) will start to grow. It’s normal for one testis to grow faster than the other. You can reassure your child that men’s testes usually aren’t the same size.
Pubic hair will start to grow. It will get darker and thicker over time.
Around 12-14 years
Your child will have a growth spurt. Your child will get taller and their chest and shoulders will get broader. Some parts of your child’s body – like their head, face and hands – might grow faster than their limbs and torso. This might result in your child looking out of proportion for a while. On average, boys grow 10-30 cm. They usually stop growing at around 18-20 years.
It’s common for boys to have minor breast development. If your child is worried by this, it might help your child to know it’s normal and usually goes away by itself. If it doesn’t go away or if the breasts seem to be growing a lot, consult your GP.
Around 13-15 years
Hair will start growing on other parts of your child’s body – under the arms, on the face and on the rest of the body. Leg and arm hair will thicken. Some young men will grow more body hair into their early 20s.
The hormone testosterone is produced, which stimulates the testes to produce sperm.
Your child might start having erections and ejaculating (releasing sperm). During this period, erections often happen for no reason at all. Just let your child know that this is normal and that people don’t usually notice. Ejaculation during sleep is often called a ‘wet dream’.
Around 14-15 years
The larynx (‘Adam’s apple’ or voice box) will become more obvious. Your child’s larynx will get larger and their voice will ‘break’, eventually becoming deeper. Some boys’ voices move from high to low and back again, even in one sentence.
