Scientists at the Chemical Senses Center in Philadelphia and its counterpart in France discovered the existence of human pheromones in 1986. They found these chemicals in human sweat . A human VNO has also been found in some, but not all, people. Even if the VNO isn't present in all of us -- and may not be working in those who do have it -- there is still evidence that smell is an important aspect of love (note the booming perfume industry). Researchers conducted an informal experiment using identical twins. Both twins sat at a bar for an evening, and one of them was sprayed with manufactured pheromones. The result was that the twin who got the pheromone boost was approached three times more often than the twin who didn't.