Random differences between cells early in development could be the key to making different cells in the body, according to new research from a team co-led by Professor Wolf Reik. Different cell types – brain, blood, skin, gut etc. – all have unique and vital roles, yet they all start out the same. Cells become different as a result of a long sequence of biochemical choices made before we’re born. For us to be healthy, these choices need to ensure we get the right number of each cell type.