It's a familiar scene for many of us. A warm summer evening, a gentle breeze and then the inevitable high-pitched whine of a mosquito buzzing near your ear. For some, this is a fleeting annoyance, but for others, it means a night of endlessly scratching itchy welts. Some people are simply mosquito magnets while others emerge relatively unscathed. But why is this so? One explanation, according to scientists from the Netherlands, is beer.