Many different theories have been put forward over the years to explain the existence of the phenomenon of handedness. Although none appear conclusive and definitive on their own, a combination of them paints a reasonably plausible and convincing picture.

Thus, the genetic theories seem to offer perhaps the most cogent and comprehensive explanations for natural handedness, the genetic base being spread throughout the species according to evolutionary laws, although it may also be influenced to a limited extent by biological factors, and even potentially altered by societal and environmental effects.

The various theories can perhaps be usefully divided into the following categories:

• Neurological Theories
• Biological Theories
• Genetic Theories
• Evolutionary Theories
• Societal and Environmental Theories
• Other Theories