The changes that occur in humans on sexual maturity are collectively referred to as secondary sexual characters. Some of these changes are common to both the genders, whereas some changes occur specific to one gender.

The changes common to both sexes are:

1. Growth of thick hair in armpits and genital area.

2. Darkening of armpits and genital area.

3. Growth of thin hair on arms, legs and face.

The changes occurring in girls:

1. Enlargement of breasts

2. Darkening of the area of nipple

3. Beginning of menstruation.

The changes occurring in boys are:

1. Appearance of thick hair on face.

2. Cracking of voice.

3. Enlargement and erection of penis.