A friend of mine has a brother who is an evolutionary psychologist and he told me once that in different periods in their menstrual cycle, women are more drawn to certain voices. When they are ovulating, they are drawn to men with deeper voices, because it signifies that they have more testosterone, and are more likely to fertilize the egg. In other parts of the menstrual cycle, they are drawn to higher voices because they are searching for a more nurturing/caretaking male. He said this theory had been studied and scientifically proven, but who knows? Interesting, though.