Most of the people in the world do most of their work with the help of their right hands. But 9 to 15% of the world population is left handed. Many famous people like Leonardo Da Vinci, Abraham Lincoln, etc were left handed.
Do you know why some people are left handers? If we examine the constitution of our body carefully, we will notice that our body is not fully symmetrical. There is a little asymmetry between the left and the right side of the body. Generally right side is more heavier than the left parts. Even the function of these parts are somewhat different. Usually the left half of the brain is predominant over the right half. In such cases, the nerves from the brain cross over at the level of the neck and go to the right side of the body. Such persons are right handed. Most of the world fall under this category. But there are the cases, where right half of the brain is predominant over the left, nerves coming out of the brain pass on to the left parts of the body. Such people perform all their functions with their left hands. This is why some children write and even eat food with left hand.
People whose right hemisphere of the brain is dominant are left handers