Growing up, we were told that deciding whether we wrote with our left or right hand was down to what felt right.
However, it turns out that the decision is made before we're even born.
According to science, the answer can be found within a network of genes. This network establishes the differences between using your right or left hand, and then influences the favoured hand while the embryo develops from a ball of cells into a growing organism.
Despite the decision coming down to genes, there seems still to be some bias, as an overwhelming 90% of people are right-handed. However, the reason for more people being right-handed is not entirely known.
As children grow older, they then show signs of favouring one or other hand as they begin to draw and write more.