Testosterone has a bad reputation. The public image of it is closely linked to the idea of dumb aggression, to the caveman. But this is a far from complete image. In recent years new research is starting to show that it would be more accurate to associate this much maligned hormone with Newton, Da Vinci, Einstein and Edison than the rough and brutal Neanderthal. Testosterone, it seems, could be the true driver of our civilisations. Satoshi Kanazawa at the University of Canterbury, New Zealand, studied the biographies of 280 scientists and plotted their intellectual achievements against their ages. He discovered...