Throughout childhood both men and women have light soft hairs on their body called vellus hairs. However, at puberty, the testis in men and the ovaries in women become active.
Consequently, more testosterone is produced in male bodies than in female bodies, which cause what we know as masculine body traits for example facial hair. Women also produce oestrogen more than men, which cause feminine body traits such as breast growth and widened hips.
Although both men and women have androgens which cause hair to darken and thicken under the arms and in pubic areas, men have more androgens than women which cause hair to additionally appear on the face, upper lip and chest. This stage of puberty usually arrives during the teenage years and most commonly between fourteen and sixteen years of age.
The term that is used for the growth, cultivation and grooming of facial hair is pogonotrophy.
The male growth of facial hair is often culturally associated with wisdom and virility. However, it is a common misconception that the ability of a man to grow facial hair is linked to their levels of testosterone when in fact it is how one's body responds to the testosterone in the body that is more relevant.
This response level is genetic and therefore can be inherited from your parents. Being highly sensitive to testosterone usually means you can grow more facial hair. However, it can also mean that you are more prone to baldness in later life.