US scientists from the Monell Chemical Senses Centre in Philadelphia have concluded that catching a whiff of someone\'s body odour can tell you whether they are young, middle aged or elderly without even seeing the person. It appears that young people have a stronger and more unpleasant scent. The smell of elderly people is the most distinctive but referred to by a group of volunteers as less intense and unpleasant. Researchers say the change in our smell is driven by the chemicals that our body releases and the changes in our skin’s bacterial flora. Their conclusions are based on a series of samples from three groups of 12 to 16 donors, aged 20 to 30, 45 to 55 and 75 to 95.