Before sex evolved on our planet, two billion years ago, all reproduction happened asexually. So why and how did sexual reproduction evolve?

Dr Lixing Sun is Distinguished Research Professor in behavior and evolution at Central Washington University. In a new book, On the Origin of Sex, he explores the fascinating, varied and complex ways reproduction happens across the natural world: from whiptail lizards, capable of immaculate conception, to clownfish and bearded dragons who regularly switch gender roles.

In this episode he sat down with Dr Güneş Taylor to explore the biological advantages of sexual reproduction, the differences between sex and gender and the variety of ways in which our planet is populated.

On The Origin of Sex: The Weird and Wonderful Science of Reproduction by Dr Lixing Sun, is available now online and in stores.