During the first year of the baby's life, all the hairs on the head grow at the same rate. At that time the head carries an even covering of hair. Then the individual hairs begin to grow independently, at different rates and in different cycles (you will read about hair growth cycles later in this chapter). Growth patterns called 'mosaics' develop.
  Many children's hair shows features which are lost in adulthood. These include:

• unruly hair which sticks straight up
• natural curls
• hair without pigment, which darkens as the child grow

Adolescence

Before puberty, the scalp carries a mixture of short vellus-like hairs and longer terminal hairs, together with various 'in-between' hairs. After puberty, in both sexes, most of the scalp hairs are terminal hairs. These hairs are thicker in diameter than the childhood hairs, especially in dark-haired people.
   At puberty, terminal hairs begin to appear in the armpits, groins and legs, and also (in males) on the chin, chest and forearms. How much body hair you develop is genetically determined (that is, it is inherited from your parents).