As your child grows, it's exciting to watch unique traits, interests, and skills emerge. One of the earliest is handedness, though it takes years of development before a consistent preference stabilizes. Keep reading for handy facts about how a child becomes a lefty, righty, or both.
1. Hand preference starts before birth.
Ultrasound studies have shown fetuses displaying a thumb-sucking preference as early as 13 weeks! This often predicts which hand a baby will favor after birth, but not always.
2. Genetics play a role in handedness.
Left-handedness tends to run in families, and identical twins are more likely than fraternal twins to have the same dominant hand. However, there's no single "handedness gene." Instead, researchers believe several genes, plus non-genetic factors, contribute to handedness.
3. Handedness is related to brain lateralization.
Handedness is closely linked to how the brain divides labor between its two hemispheres. In most right-handed people, language processing is concentrated in the left hemisphere, which controls the right side of the body. Left-handed people have more varied brain organization. Many have left-hemisphere language dominance, but a higher percentage show right-hemisphere or shared language processing.
4. Hand preference emerges gradually.
Once baby masters hand-eye coordination, they'll reach for toys and other objects with their closer hand. You may initially see them eat, paint, or draw with both hands interchangeably or simultaneously. A consistent hand preference stabilizes around 2-4.
If you notice your child showing a strong, fixed hand preference before they're 12 months old, especially if the other hand seems weaker and much less used, contact your child's pediatrician. This could indicate a motor or neurological issue.
5. Left-handers are in the minority.
Around 10% of the population is left-handed. This rate has held steady over generations. Boys are slightly more likely to be left-handed than girls—another aspect of handedness that isn't understood.
6. In past generations, left-handedness was suppressed.
For much of history, left-handed children were forced to write and eat with their right hands, due to stigmas and religious beliefs that using the left hand is unclean or abnormal. This practice has mostly disappeared in Western countries, but some Middle Eastern, African, and South Asian communities still discourage left-handedness. It's unfortunate, because deterring a child's natural hand preference creates coordination difficulties and is very frustrating.
7. Mixed-handedness is real.
Not every child lands neatly on left- or right-handed Some children are cross-dominant and use different hands for different tasks. Writing with one hand, for example, and playing sports with another. Others are truly ambidextrous, using both hands with the same dexterity and ease. This is a normal variation, not a developmental red flag.
8. Handedness isn't a measure of skill or intelligence.
Despite all the myths, there's no meaningful link between handedness and a person's cognitive ability, creativity, or athletic potential. The best thing you can do to support your child's development is to give them plenty of opportunities to explore their world on their own terms. Time and experience will reveal your little one's dominant hand and all the other traits that make them unique.