It’s a mixture of your genes which you get from your parents, and also your life experience.
A study of more than 1.7 million people has revealed 41 distinct genetic regions associated with left-handedness, and another 7 tied to ambidexterity.
Rare left-coiled shells in garden snails turn out to be a developmental accident not an inherited trait.
10% of people are left-handed but we still haven’t uncovered how this changes the way their brains work.
Handedness is the tendency to prefer using one hand over the other to perform certain tasks. But how did we get this way?