Think of all the efforts that women make to look younger — and it turns out that all they needed was a little citrus fruit. The Smell and Taste Institute of Chicago wanted to determine what makes a woman smell younger to men. Banana, lavender and other odors made no difference. But the smell of grapefruit caused men to believe that women were, on average, about six years younger than reality. The reverse is not true. Women were not fooled by the scent on men.