Philip Ball has written over 20 books about molecular chemistry and science in the 21st century, as well as works of biography and fiction. His latest book is How to Grow a Human, a work in which Ball, based on an experiment carried out on cells extracted with his own skin, explains to the reader how almost any kind of cell can be converted into another, different kind. Would it be possible to create a complete human being? In conversation with the BBC Mundo journalist, Juan Carlos Pérez.