Why do some people have little body hair while others are hairy?

[Jekertee]

Except the genetic factors, why do some people not have a single hair on legs or arms while some are full all over the body ? I rarely see North American men without facial hair.

On the ads I have read, there are even cream or medicine that helps hair growing. that's really funny. Is it good for the health ?

 

[Moonbear]

Other than genetic factors, there's shaving, depilatories (chemicals that make the hairs fall out), electrolysis (a small electric "shock" is given to the root to kill the hair cell), laser treatments (performed in a doctor's office), waxing and plucking (both are means of ripping the hairs out...OUCH!) And, of course chemotherapy can lead to hair falling out as well.