That's actually a really easy question. We look at people's bedroom behavior. There's a whole scientific field on this sort of thing: http://en.wikipedia.org/w

That's actually a really easy question. We look at people's bedroom behavior. There's a whole scientific field on this sort of thing: http://en.wikipedia.org/wiki/Sexology http://en.wikipedia.org/wiki/Sexology Alfred Kinsey, for example, got his fame by scientifically studying what's normal in bedrooms, and publishing this information.