What’s morality got to do with it?

Every generation lives a little longer than the last — it’s the sign of an advancing society. A hundred years ago the average British life expectancy at birth was 45. Now it is 75, giving us a blissful free decade at the end of our working lives to spend fending off great-grandchildren and watching wide-screen television. The downside is that as we live longer and as doctors become better at warding off death, we pass an ever greater percentage of our lives suffering. Heart attacks, strokes, cancer, diabetes, liver failure, blindness, senile dementia, Parkinson’s disease, Huntington’s, Alzheimer’s, arthritis. Whereas we used to fall sick and die off quite quickly, most of us now spend our last 15 years ailing in one way or another — but what can we possibly do about it?

The short answer is to be found in stem cells — the basic blobs out of which every other sort of tissue develops.