Extensive column inches have been devoted to the coverage of stem cells. They’re being heralded as the next miracle therapy for everything from Parkinson’s and spinal cord injury to heart disease and diabetes. On the other hand, embryonic stem cells are often in the news for the contentious ethical debates they raise on topics such as human cloning or the use and destruction of embryos for research.

Scientists are neither heroes nor villains. So what’s the truth behind the often, rather dramatic headlines? What are the benefits and limitations of the different types of stem cell? What is the realistic prospect for therapies? And where will research (particularly epigenetic research) take us next? Acting as a lighthouse of common-sense in the fog of confusing media hype, here it is: your definitive stem cell guide.