Puberty: Tanner Stages for Boys and Girls (2025)

What is the purpose of puberty?

Puberty is your body’s natural way of physically becoming an adult. It’s the period of time when your major organs and body systems mature, and your body becomes capable of sexual reproduction. You experience mental and emotional development as well during puberty.

Although puberty makes you physically an adult, your brain continues to develop and mature into your mid-to-late 20s.

When does puberty start?

Puberty starts when a part of your child’s brain called the hypothalamus begins producing a hormone called gonadotropin-releasing hormone (GnRH).

Their hypothalamus sends GnRH to another part of their brain called the pituitary gland. GnRH stimulates your child’s pituitary gland to release two more hormones — luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

These hormones travel to the sex organs (gonads) — the ovaries or testes. This triggers your child’s gonads to begin releasing sex hormones — either estrogen or testosterone. These messenger hormones cause the telltale signs of puberty to begin.

When do girls start puberty?

Puberty for girls (children with ovaries) usually starts between the ages of 8 and 13. This is typically two years before boys. Black and Hispanic girls tend to start puberty earlier than white girls (age 7 1/2 instead of 8).

When do boys start puberty?

Puberty for boys (children with testes) begins sometime between the ages of 9 and 14. Boys hit puberty about two years later than girls. However, Black and Hispanic boys tend to enter puberty a bit earlier than white boys.

What are the tanner stages of puberty?

Tanner Staging, also known as Sexual Maturity Rating (SMR), is a classification system that healthcare providers use to document and track the development of secondary sex characteristics of children during puberty.It’s a tool that outlines the stages of puberty for your child and when they’re likely to occur.

Tanner stages for girls

There are separate Tanner stages for changes in breasts and pubic hair. Other physical changes happen as well. The Tanner stages can serve as an excellent guide to the changes you can expect to see in your daughter. There are five stages of puberty for girls.

Stage 1 is prepubertal. In this stage, girls haven’t experienced any visible changes. But their adrenal glands are maturing and their ovaries are growing.

In Stage 2, physical changes begin. Between the ages of 8 and 13, girls typically experience:

Budding breasts and enlargement of areolas (pigmented area around their nipple).
Scant pubic hair along their labia.
Height increases by about 2 3/4 inches per year.
Enlargement of their clitoris.
Growth of their uterus.
They may start having body odor. Deodorant can help.

In Stage 3, physical changes speed up. Between the ages of 9 and 14:

Breasts continue budding.
Armpit (axillary) hair begins to grow and pubic hair continues to grow. Pubic hair is coarse, curly and forms in the shape of an upside-down triangle.
A growth spurt of more than 3 inches per year occurs.
Oilier skin leads to acne.

In Stage 4, puberty hits full stride. Between the ages of 10 and 15:

Breasts continue growing, and their areola (the part that’s red or darker at the nipple) forms a separate mound over the mound of breast tissue.
Pubic hair is still in a triangle, and there are now too many hairs to count.
Growth may continue at the rate of about 2 3/4 inches per year.
Acne may continue.

Periods (menstruation) begin in Stage 4, typically around age 12 (usually around the same age their biological mother’s and sisters’ periods began). Some girls start earlier or later than this age. Periods usually start around two years after breasts start to bud or pubic hair starts to grow. If periods haven’t started three years after puberty began, make an appointment with your child’s healthcare provider.

Stage 5 is the final phase. Development typically ends in this stage. Girls reach physical adulthood. Pubic hair may extend out to their thighs, and some girls may have a line of hair up to their belly button. Most girls reach their peak height by age 16, but some may continue growing through age 20. Some girls never have pubic hair reach Tanner Stage 5; that may be their “normal.”

Tanner stages for boys

There are separate Tanner stages for changes in genitalia and pubic hair. Other physical changes happen, too. For parents, the Tanner stages can serve as an excellent guide to the changes you can expect to see in your son. There are five stages of puberty for boys.

Stage 1 is prepubertal. In this stage, boys haven’t experienced any visible changes, but their adrenal glands are maturing.

In Stage 2, physical changes begin. Between the ages of 9 and 14, boys typically begin to experience:

Genital development (growth of their testicles and scrotum).
Growth of sparse hair around their penis and under their arms.
An increase in height (typically about 2 to 2 1/2 inches per year), which could bring growing pains.
Changes in body composition with a decrease in body fat (adipose tissue).
They may start to have body odor and may need deodorant.

In Stage 3, physical changes speed up. Between the ages of 10 and 16 years, boys experience:

Continued growth of their penis and testicles. Nocturnal emission (“wet dreams”) may happen as well.
Darkening, coarsening pubic hair in the shape of a triangle in their genital area.
Continued increase in height (about 2 3/4 to just over 3 inches per year).
More sweating, which can lead to body odor.
Vocal changes (and cracking in the process).
Increased muscle mass.

Some breast development, or gynecomastia, occurs in about 50% of all boys in Stage 3. But it typically resolves by the end of puberty. It’s most common between the ages of 11 and 15 years. If this becomes an issue physically or socially, you should talk with your child’s healthcare provider.

In Stage 4, puberty hits full stride. Between the ages of 11 and 16 years, boys experience:

Growth in penis size and darkening of the skin on their scrotum and testicles. Red ridges on their testicles called rugae will begin to develop.
Body hair growth that reaches adult levels. Pubic hair remains in a coarse triangle.
A peak growth spurt that averages nearly 4 inches per year.
Development of acne.
Continued cracking of their voice.

Stage 5 is the final phase. Puberty ends in this stage. Boys finish their growth and physical development.

Many may not develop facial hair until this step in the process. Pubic hair may extend out to their thighs, and some boys may have a line of hair up to their belly button. Most boys finish growing by age 17, but some may continue growing through their early 20s.

How does puberty affect emotions?

When your child enters puberty, you may or may not see some emotional upheaval. Surges in sex hormones, coupled with social pressures, may cause moody behavior, emotional outbursts and family discord.

Your child is going through drastic changes in their identity and social life. They may develop confidence issues or feel many different emotions related to their sexuality, like desire, confusion and fear.

If serious emotional or behavioral problems arise — signs of anxiety, depression, extreme mood swings or aggression — it’s important for your child to see their healthcare provider. Your child may benefit from psychotherapy (talk therapy) and/or medication.

Gender dysphoria can also arise during puberty. Be sure to support your child and help them get the professional care they need.

When does puberty end?

For girls, puberty typically ends around age 15 to 17 years. For boys, it tends to end around age 16 to 17 years. Again, every child is different, so these ages can vary.

How long does puberty last?

Puberty typically lasts two to five years. But every child is different. It can be difficult to not know how long puberty will take. But know that your child’s body is going through a natural phase of life.