Research is revealing that male and female brains are built from markedly different genetic blueprints, which create numerous anatomical differences. There are also differences in the circuitry that wires them up and the chemicals that transmit messages between neurons. All this is pointing towards the conclusion that there is not just one kind of human brain, but two. The research contradicts the long-held theory that the differences in the way the sexes think are caused by social pressure and upbringing, or the action of sex hormones. The gender gap has only just come to light because neuroscientists have traditionally carried out their studies on male brains, be they animal or human. Pain researcher, Jeff Mogil, of McGill University said: 'It's scandalous. 'Women are the most common pain sufferers, and yet our model for basic pain research is the male rat. 'Every year or two, we write a paper that says that something someone reported earlier is actually only true in males. 'We keep making people look bad. They are missing stuff completely.'