An ideological dispute is taking place in biology. And it’s about a big topic that’s central to everything: heredity. In his epoch-making book On the Origin of Species of 1859, Darwin wrote of the reigning ignorance about how differences between individuals come about. It was only with ‘modern evolutionary synthesis’ in the 1940s that people became convinced that heredity functions through genetics – in other words, that the characteristics of living creatures are passed on to the next generations through their genetic substance, DNA.