Physical Development in Adolescence (9-18 years)

Adolescence is a time of significant physical change.

The major physical change is puberty. Puberty happens when a child’s body starts to change in preparation for adulthood. During puberty, physical changes to male and female reproductive systems mean individuals are able to reproduce.

Physical changes in puberty include the development of the primary and secondary sexual characteristics.

Primary and Secondary Sexual Characteristics

Primary sexual characteristics are processes related to the sex organs which are present at birth and mature when sex hormones are released, whereas secondary sexual characteristics mature during puberty.

Puberty is governed by the increase of hormone production. Hormones are produced by glands and are chemical messengers that coordinate growth and development.

Puberty in Females

• In females, the pituitary gland sends a message to the ovaries which then produces the hormones, oestrogen and progesterone. These hormones will cause the development of the primary and secondary sexual characteristics.
• The initial signs of puberty in girls is that their breasts start to develop, and they may notice more hair growing on their arms and their legs.
• This is followed by further breast development and, usually two years after this, they may experience their first period. Pubic hair starts to grow under the arm pits and becomes coarse. Girls may notice they start to sweat more and may get acne.
• More white vaginal discharge starts to be produced and they are likely to go through a growth spurt and gain weight. Weight gain is a normal part of puberty and is part of the transition to adulthood. More body fat is found around the arms, thighs and back.
• Hips become rounder and the waist becomes narrower.
• Around four years into puberty, girls stop growing, pubic hair grows around the inner thigh area and genitals and breasts are now fully developed.

Puberty in Males

• The pituitary gland sends a message to the testicles to produce the hormone, testosterone. This will cause the development of the primary and secondary sexual characteristics.
• The first signs of puberty for boys are indicated by pubic hair appearing around the base of the penis and the testicles enlarging.
• In a similar way to girls, as boys go through puberty they go through a growth spurt, gain more pubic hair, start to sweat more and may have acne.
• Four years after puberty, boys’ genitals look like an adult’s and pubic hair has spread to the inner thigh. Boys may stop growing at 16 but may start to become more muscular. Many males may also have facial hair at this stage too.