The urge to reproduce, to pass on our genes to a new generation, is one of the most powerful in our lives. This is equally true of the bewildering variety of animals with whom we share the planet. And they have an equally bewildering variety of ways of going about it.

Our opinion editor Amanda Gefter recently visited an exhibition entitled The Sex Lives of Animals, which seeks to overturn the idea that animals engage in sex purely for procreation. By doing so, it taps into a wider debate about which sexual behaviours can be seen as "natural". (From NewScientist)