If scientists from another planet were trying to understand us, our obsession with privacy during sex would make a good thesis project. The aliens might have noticed that most humans prefer to copulate while hidden away - in our cozy bedrooms or perhaps on a desolate beach dappled with moonbeams. Much fuss ensues when someone chooses to perform mating behavior more publicly, say in a sex club, or in front of a University of Pennsylvania dormitory window. Why, the aliens might wonder, would crowds of humans gather to watch and photograph a pair of other humans at Penn who repeatedly...
