Sir John Gurdon talks to Jim al-Khalili about how coming bottom of the class in science was no barrier to winning this year's Nobel Prize for Physiology or Medicine. We're familiar with Dolly the Sheep but many people find the idea of cloning humans rather disturbing. It seems to cut to the core of who we are; but, scientifically speaking, we are getting closer to a time when cloning people might be possible. John Gurdon gives it fifty years. After a famously bad school report for science, he won the Nobel Prize for cloning a frog, decades before Dolly the Sheep. He talks to Jim al-Khalili about his pioneering work on cloning and where it all might lead.