Why We Are Right-Handed – The Evolutionary Mystery of the Dominant Hand

The article explains why about 90% of people are right-handed and 10% are left-handed, citing biological and evolutionary reasons. Hand preference forms as early as the 10th week of pregnancy. DNA studies of over 1.7 million people have shown that dozens of genome regions are responsible for left-handedness. The evolutionary shift is linked to bipedalism and tool use. Left-handers have not disappeared because their unconventional movements provided an advantage in combat. Retraining left-handers is harmful.

Approximately 90% of the world's population is right-handed, and only 10% are left-handed. This ratio is stable across all cultures and continents. Scientists attribute this to deep biological and evolutionary processes. Hand preference begins to manifest as early as the 10th week of fetal development: the fetus more often moves its right hand. The left hemisphere of the brain controls the right side of the body and contains speech centers. A large-scale DNA analysis of over 1.7 million people showed that dozens of genome regions, not a single gene, are responsible for left-handedness and ambidexterity. The evolutionary shift toward right-handedness is linked to bipedalism and the freeing of hands for tool making. Archaeological finds from Spain (Sima de los Huesos site) and analysis of Neanderthal remains show that most people were right-handed as early as 500,000 years ago. Left-handers did not disappear, possibly due to an advantage in combat. Experts emphasize that left-handedness is normal and retraining is harmful.