A Crack in Creation

304pp, Bodley Head, £20, ebook £9.99

Designer babies have long been the stuff of science fiction or scary thought experiments. Now we are on the cusp of making them possible, thanks to the new science of gene editing, explained here excitingly and clearly by two of its architects. But if you can buy strength or health in your unborn baby, will a “gene gap” be added to society’s other inequalities? This study rightly fears it, but relies on a specious “slippery slope” argument. Steven Poole