The Enchantments of Flesh and Spirit (Wraeththu Series #1)

The world is changing. While human civilisation implodes, a new race is rising from the debris. Pellaz, a human boy, is drawn into the world of Wraeththu by the enigmatic Cal. In order to survive, Pellaz must transform into a new being, neither male nor female but something of both. Pellaz discovers that his inception has marked him for a destiny, both terrifying and wonderful.