Every century is different - but the 21st may be seriously different, with our ability to understand, modify and re-create humanity having come on light years in recent decades. Should we? So often, the warning we hear when it comes to the scientific manipulation of the human is that we shouldn't "play God". But what grounding does that actually have? What if we actually are a "playing God" species? Kicking off a new series of Reading our Times, this one dedicated to the overall theme of Playing God, Chine McDonald talks to Nick Spencer about his new book, co-authored with Hannah Waite, Playing God: science, religion and the future of humanity