In 1797, the English clergyman Thomas Gisborne wrote a popular book called, An Enquiry into the Duties of the Female Sex. It outlined the different mental abilities of men and women and was a Victorian best-seller. Today many scientists believe there is a male and female brain. Australian academic psychologist Cordelia Fine begs to differ. She has written several books about brain development and the science of sex differences. The latest is Delusions of Gender: The Real Science Behind Sex Differences. Cordelia Fine speaks with IDEAS producer Mary O'Connell.