Lab notes: swimmers put the 'pee' in pool and other wee scientific breakthroughs

In a week in which Cambridge scientists created first artificial embryo from stem cells, the world's oldest fossils were found in Canada and a heart tissue cryogenics breakthrough gave hope to transplant patients around the world, what were our readers most interested in? Wee in swimming pools. That's right, watersports fans: urine luck, because scientists have developed test designed to estimate how much urine has been covertly added to a large volume of water. For the swimmers amongst you not keen to find out how polluted your pool is, console yourself - we did have other stories as well, including the intriguing news that woolly mammoths may have been silky-coated and suffering from a host of genetic mutations that aided their decline. Ok, it's a bit of a downer, as is the news that being overweight (not just obese) is linked to an increased risk of 11 types of cancer, but don't despair: we've got the answers to some of your questions on orgasm - most enlightening!