Puberty

Puberty is the time when a child's body changes into an adult body, getting ready for the possibility of having babies. It starts when the brain sends special messages to parts of the body called the ovaries in girls and the testicles in boys. These parts then make new chemicals that cause many changes in the body, like growing taller, growing hair in new places, and developing features that make boys and girls look different.

Girls usually start puberty around age 10½ and finish by ages 15–17. Boys start a little later, around ages 11½–12, and finish by ages 16–17. For girls, a big sign that puberty has started is their first period, which usually happens around age 12½. For boys, a big sign is their first time producing sperm, which usually happens around age 13.

In recent times, children seem to start puberty a bit earlier than they did in the past. This might be because they are healthier and have better food, but it could also be affected by things in the environment. No matter when it starts, puberty is a normal and important part of growing up, helping children become adults.

Differences between male and female puberty

Puberty is when kids start changing into adults. Girls usually start around age 10½, and boys start a bit later, around 11½ to 12. For girls, this process usually finishes by age 15–17, while for boys it can go on until about 16–17.

Boys produce a hormone called testosterone, which helps them grow deeper voices and more muscle. Girls produce hormones like estradiol, which helps their bodies get ready for future families. Boys often grow taller than girls after puberty because their growth happens more slowly over a longer time.

Puberty onset

Puberty is the time when a child's body changes to become an adult body. Before puberty starts, there is a change called adrenarche, which happens between ages 6 and 10. This change can cause hair to appear in certain areas of the body.

The start of puberty is linked to signals from the brain. These signals can cause changes in the body that lead to puberty beginning earlier than usual. Scientists think that a substance called leptin, which helps control hunger, may play a role in starting puberty. Some genes may also affect when puberty begins.

Effects of early and late puberty onset

Studies have looked at how starting puberty early or late affects boys and girls. For girls, starting puberty early can be challenging. They may feel self-conscious about their changing bodies and face teasing from others. This can affect their confidence and mood. Girls who start puberty later often have easier times during their teenage years.

For boys, starting puberty early used to be seen as an advantage. But newer research shows that early-maturing boys may face problems such as feeling angry or getting into trouble. Boys who start puberty later might feel less confident and struggle with feelings of anxiety.

Changes in males

Changes in females

The first sign that a girl is going through puberty is usually the growth of her breasts. This starts with a small, tender lump under the center of the breast area. Over time, the breasts grow and change shape.

Another change is the growth of hair around the pubic area. This usually starts a little after the breasts begin to grow. Hair may also grow under the arms later on.

During puberty, a girl’s body also changes shape. Her hips may widen, and she may notice more body fat, especially in areas like the breasts, hips, and thighs. This helps prepare the body for future growth and changes.

Many girls also notice changes in their skin and smell during this time. Some may experience acne, which is a common skin condition during puberty. The body may also start to smell different as sweat changes.

Eventually, most girls will have their first period, called menarche. This usually happens about two years after breast development starts. The average age for this is around 12 or 13, but it can happen earlier or later and still be normal.

The body makes many changes to get ready for adulthood, including growing new hair and changing body shape. These changes are all natural and help the body develop into the adult it will become.

Variations

Puberty ends when a person is ready to have children, usually when they reach their full adult height and their bodies are fully developed. For most girls, this happens around age 15, and for most boys, around age 18. Sometimes, a person might start puberty a little earlier or later than others, which is normal.

The age when puberty starts can vary a lot. It often begins between ages 10 and 13, but this can change depending on genetics, nutrition, and other factors. For example, girls who have more interaction with adults might start a bit earlier. The average age can also differ among different groups of people, partly because of diet and health. Some studies suggest that puberty might be starting earlier now than in the past, possibly due to factors like weight or certain chemicals in food and products.

Neurohormonal process

The body has a special system that helps start puberty. This system includes the brain, a small gland near the brain, and glands called gonads and adrenal glands. It all begins in the brain.

First, a part of the brain called the hypothalamus starts sending out special signals. These signals tell another gland, the pituitary, to release certain chemicals. These chemicals then tell the ovaries in girls or the testes in boys to start making new hormones. These hormones cause many changes in the body during puberty.

The start of this process can happen a little before we see any changes in the body.


Hormone	Units	Prepubertal Stage 1	Stage 2	Stage 3	Stage 4	Stage 5
Hormone	Units	Prepubertal Stage 1	Stage 2	Stage 3	Stage 4	Phase
LHTooltip Luteinizing hormone	mIU/mL	2.7 (	4.2 (	6.7 (	7.7 (2.8–15.0)	Follicular Luteal	7.6 (3–18) 6.6 (3–18)
LHTooltip Luteinizing hormone	U/L		0.7 (	2.1 (	3.6 (0.9–8.1)	Follicular Luteal	3.8 (1.6–8.1) 3.5 (1.5–8.0)
FSHTooltip Follicle-stimulating hormone	mIU/mL	4.0 (	4.6 (	6.8 (3.3–10.5)	7.4 (3.3–10.5)	Follicular Luteal	10.3 (6–15) 6.0 (3.4–8.6)
FSHTooltip Follicle-stimulating hormone	U/L	2.1 (	3.5 (	4.9 (0.7–9.0)	6.2 (1.1–11.3)	Follicular Luteal	6.6 (1.9–10.8) 5.4 (1.8–10.5)
Estradiol	pg/mL	9 (	15 (	27 (	55 (16–85)	Follicular Luteal	50 (30–100) 130 (70–300)
Estrone	pg/mL	13 (	18 (10–37)	26 (17–58)	36 (23–69)	Follicular Luteal	44 (30–89) 75 (39–160)
Progesterone	ng/dL	22 (	30 (10–51)	36 (10–75)	175 (	Follicular Luteal	35 (13–75) (200–2500)
Hydroxyprogesterone	ng/dL	33 (	52 (10–98)	75 (10–185)	97 (17–235)	Follicular Luteal	48 (12–90) 178 (35–290)
DHEA-STooltip Dehydroepiandrosterone sulfate	μg/dL	49^a (20–95) 106^b (40–200)	129 (60–240)	155 (85–290)	195 (106–320)	–	220 (118–320)
DHEATooltip Dehydroepiandrosterone	ng/dL	35^a (127^b (72–180)	297 (150–540)	328 (190–620)	394 (240–768)	–	538 (215–855)
Androstenedione	ng/dL	26 (	77 (40–112)	126 (55–190)	147 (70–245)	–	172 (74–284)
Testosterone	ng/dL	10 (	18 (	26 (	38 (24–62)	–	40 (27–70)
Notes: Values are mean plasma levels, with ranges in parentheses. ^a = Pre-adrenarche. ^b = Post-adrenarche. (Adrenarche, or increased adrenal androgen section, occurs as a separate event and can precede puberty onset by 1 to 2 years.) Sources:

Stages

Puberty happens in several stages. One of the first signs is adrenarche, which usually starts between ages 6 and 8. Next comes gonadarche, around age 10½ for girls and 11½ for boys. In girls, thelarche — the growth of breasts — often begins around age 10½. Pubarche, the growth of pubic hair, typically starts around age 11 for girls and age 12 for boys. For girls, menarche — the first menstrual period — usually happens around age 12½. In boys, spermarche — the first release of sperm — often occurs around age 13.