PolygamousRanchKid writes with an article exploring the question posed in the headline, which says that "One answer may lie in biology. Scientific studies have shown that people generally find women's voices more pleasing than men's. 'It's much easier to find a female voice that everyone likes than a male voice that everyone likes,' said Stanford University Professor Clifford Nass, author of 'The Man Who Lied to His Laptop: What Machines Teach Us About Human Relationships. 'It's a well-established phenomenon that the human brain is developed to like female voices.' One notable exception has been Germany, where BMW was forced to recall a female-voiced navigation system on its 5 Series cars in the late 1990s after being flooded with calls from German men saying they refused to take directions from a woman. An Apple spokeswoman declined to comment on why the company gave Siri a female voice in the U.S. Nor would she say why Siri speaks like a man in the UK, where iPhone 4S owners have swarmed online forums to request a female voice instead."