Looking at our bodies, one can see that our left side is different from our right side. Our hands, for example, are mirror images of each other meaning that they can’t be laid on top of each other so that they match. Other parts of our bodies are the same, like the brain where the left and right hemispheres are responsible for different tasks. Zooming in further, the molecules that make up your body often are also chiral (mirror images of each other). This property of chirality is common to all higher organisms, but we do not really understand how this comes about. What are the first steps that establish something asymmetric from a perfectly symmetric egg? Also, what role do chiral molecules play in making the chiral pattern of the body? These are fundamental riddles of development. If the development is disturbed, results can be benign as in the case of situs inversus (heart on the right side) or more severe, in the case of congenital heart defects (where the structure of the heart does not form properly as the foetus grows). The aim of this project is to provide a unifying answer to these questions that encompasses both physics and biology. It will therefore foster our basic understanding of how animals come to look as they do and inform us about how humans do as well.