Before the age of 18 months, babies often use both hands equally and hand preference usually rely on which hand is closer to the desired object. For example, a toddler may reach for a toy on their left side with their left hand because of convenience, regardless of future hand preference.
By the age of about 18 months, most toddlers have a preference for using one hand or the other, and are definitely right or left-handed by about the age of three. Often, parents will assume that the hand with which the child catches or throws a ball is the dominant hand, but that isn’t always the case. By observing everyday tasks are more accurate in predicting the handedness of your child.
Signs of left-handedness to look out for include:
Which hand your child uses to reach for items that are placed directly in front of him?
Which hand does (s)he use for grooming?
Which hand your child uses to hold a spoon when eating?
Which foot does (s)he prefer to kick with?
Which hand does (s)he use to hold a crayon or pencil?
When standing on one leg which leg does (s)he feel more secure on? Lefthanders may find it easier to stand on their left leg.
Genetics plays a part in handedness as well. 10% of the population is left handed, and twice as many males as females are lefties. If both parents have a dominant left hand, there’s a 25% to 50% chance your child will be a leftie.
If your child is naturally left-handed, don’t try to force them into using their right hand. While we know very little about what influences hand preference, we do know that handedness reflects the wiring of the individual brain.
Be aware that babies who show an exclusive hand dominance before the age of 18 months might have a motor development problem. Babies who have had injuries to the right side of the brain may show a preference for using the left hand, so preference for the right hand could signal injury to the left side of the brain that’s previously gone undetected. Any concerns should be addressed with your pediatrician.