Today – many, many billions of cell divisions later – your DNA could stretch all the way to the sun and back, around 250 times. Even though your genetic material has been copied so many times, the most recent copy is remarkably similar to the original that was once created in the fertilised egg. This is where life’s molecules display their greatness, because from a chemical perspective this ought to be impossible. All chemical processes are prone to random errors. Additionally, your DNA is subjected on a daily basis to damaging radiation and reactive molecules. In fact, you ought to have been a chemical chaos long before you even developed into a foetus.