Most babies use both hands to begin with, and rarely show any preference before about 7 to 9 months old. By about 18 months many children use one hand consistently, but 4 to 6 year old children may still be undecided as to their dominant hand.
Catching and throwing a ball is not always a good way to tell hand preference. Some ways to tell if your child is left-handed include:
About 10% of people are left-handed. Males are about twice as likely to be left-handed than are females. Several genes contribute to the preference of a child to use the left hand for most activities.
Left-handedness is related to the brain, not the hand. It is not just a habit. There is no great disadvantage to being left handed. Many famous and successful people throughout history were left handed.
Left-handedness is more common in children with who have had injuries to the right side of the brain, just as right-handedness is more common in children with left-sided brain injuries. If you have concerns, have your child checked by your healthcare provider.
If you are right-handed, sit across from your child when teaching them to tie their shoe laces or get dressed. This gives them a mirror image to copy, and is easier than sitting beside them to demonstrate.
Lefties have to get special left-handed golf clubs, hockey sticks, and baseball mitts. They usually can't just borrow friends' equipment.
Left-handers should only use scissors designed for them. Scissors and saws for right-handed people can be dangerous for lefties. When your child reaches school age, make sure that he or she doesn't have to sit at desks for right-handers. When students begin to write, they should learn paper and pencil positions for the left-hander. For example, it helps for the left-hander to hold her or his pencil a little higher than the right-hander.