Is there a test that tells you how long you’ll live? If you read and believed some newspaper headlines in recent months, you might think so. The claim surrounds an area of ageing research known as telomere biology. Telomeres are DNA structures which cap the ends of our chromosomes. They shorten over the course of our lives. Some scientists believe measuring their length reveals how fast we are ageing biologically and are making telomere tests available to the public for the first time. What’s the science behind telomere length and what can it really tell you about your heath and life prospects? Andrew Luck-Baker reports from a meeting of leading telomere researchers in Stockholm.