Because humans have two hands, so it divided into two skill of the human hand is "right-handed" and "left-handed" from the statistics of the general population world. The right-hander will have approximately 85% and approximately 15% is a lefty, but the people we will do it by hand. Scholars believe it since we were born with. The notice of the fetal hands near the mouth any more. Then it was the right-hand side at the time.