Most babies start showing a hand preference between 6 and 14 months of age, but it won’t become truly settled until much later. In fact, handedness often isn’t consistent and reliable until a child is 3 to 4 years old, and some children don’t fully commit to one hand until age 5 or 6. The path to a dominant hand is gradual, with plenty of switching along the way.
The First Signs: 6 to 14 Months
Researchers tracking nearly 400 infants found that a preference for reaching and grabbing objects starts appearing before 6 months, becomes more noticeable between 6 and 12 months, and then actually fades for a while. In that study, 32% of infants showed a consistent right-hand preference from 6 to 14 months, 12% showed a consistent left preference, and 26% were trending toward a right preference that hadn’t fully developed yet. The remaining babies showed no clear pattern at all.
By 10 to 11 months, babies begin using a preferred hand not just for grabbing things but also for turning objects over, poking at buttons, or exploring textures with one hand while the other holds the item steady. This is a more complex kind of hand use, and when it lines up with the hand a baby prefers for reaching, it’s an early signal of the direction handedness is heading.
Why Handedness Seems to Come and Go
Parents often notice their baby favoring one hand for a few weeks, then switching. This is completely normal. Hand preference in infancy isn’t a light switch. It develops in waves as different parts of the brain mature and as babies practice new motor skills. When a child is learning something new, like holding a spoon or stacking blocks, they often experiment with both hands before settling back into a preference. A toddler who seemed clearly right-handed at 12 months might use the left hand just as often at 18 months, then drift back to the right by age 2.
True, consistent handedness requires the brain’s motor areas to develop strong connections to one side of the body. Brain imaging studies in children show that handedness is linked to differences in functional connectivity, meaning how well different brain regions communicate during movement, rather than differences in brain structure. A left-handed child’s brain routes motor signals differently than a right-handed child’s brain, but the underlying anatomy looks the same. These connectivity patterns take years to mature.
When Handedness Becomes Reliable
For most children, hand preference solidifies gradually between ages 2 and 4. By age 3, many kids consistently reach for a crayon or spoon with the same hand. By age 4 or 5, the preference is typically stable enough that you can confidently say your child is right-handed or left-handed. Some children, particularly those who end up mixed-handed, take until age 6 to settle fully.
Globally, about 89 to 90% of people are right-handed, roughly 10% are left-handed, and around 1 to 2% are truly ambidextrous, meaning they use both hands equally well. Data from over 500,000 adults in the UK confirms this breakdown is remarkably consistent across populations.
Genetics Play a Role, but Not the Whole One
If you or your partner is left-handed, your child has a higher chance of being left-handed too, but it’s far from guaranteed. A large study of over 37,000 Dutch twins found that when one parent was left-handed, the chance of having a left-handed child increased by about 4%. When both parents were left-handed, it went up by about 10%. A left-handed mother had a somewhat stronger influence than a left-handed father, raising the odds by roughly 60% compared to right-handed mothers.
Still, the majority of left-handed children have two right-handed parents. Handedness is influenced by multiple genes working together, along with prenatal factors that aren’t fully understood. There’s no single “left-handed gene” being passed down.
How to Spot Your Child’s Preference
You don’t need a formal test. Simple observation during everyday activities gives you plenty of information, especially once your child is past their first birthday. Here are a few things to watch for:
- Reaching for objects: Roll a ball toward your toddler and see which hand they reach with. Offer a toy at their midline (directly in front of them, not off to one side) and note which hand grabs it.
- Eating: Watch which hand picks up finger foods or first holds a spoon. Toddlers often switch when muscles tire, so pay attention to which hand starts the task.
- Drawing and coloring: Once your child is old enough to hold a crayon, around 15 to 18 months, this becomes one of the clearest signals. Again, look at which hand they choose first, not which hand they end up using after switching.
- Stirring: A child who stirs in a counterclockwise motion is more likely to be left-handed, though this is an informal observation rather than a definitive test.
Try these observations on different days. A single session won’t tell you much, but a pattern over weeks or months will.
When a Strong Early Preference Warrants Attention
While mild hand preferences in the first year are normal, a baby who exclusively uses one hand and seems to avoid or neglect the other before 12 months may warrant a closer look. This is different from the typical pattern of favoring one hand. If your baby consistently ignores one hand, keeps it fisted, or seems unable to use it for grasping, that can sometimes indicate a neurological issue affecting one side of the body. The key distinction is between preference (choosing one hand more often) and inability (rarely or never using the other hand). The former is expected; the latter is worth mentioning to your pediatrician.
Similarly, children who show absolutely no hand preference by age 5, switching constantly with no pattern, sometimes benefit from an evaluation to make sure motor development is on track.
Should You Encourage One Hand Over the Other?
No. Forcing a naturally left-handed child to use their right hand, a practice that was common decades ago, doesn’t change the underlying brain wiring. It can lead to frustration, coordination problems, and difficulty with fine motor tasks. Let your child’s preference emerge naturally. Offer objects at their midline so they can choose freely, and resist the urge to place a spoon or crayon in a specific hand.
If your child is left-handed, you can help by providing left-handed scissors once they’re old enough for crafts and by sitting to their right during meals so your elbows don’t bump. Small accommodations like these make a bigger difference than any attempt to redirect their natural preference.