Why are there so few famous women scientists? Are there any inborn differences in ability or aptitude between men and women?

For over a century, starting with the phrenologists, male scientists have been searching for evidence to demonstrate female inferiority.

Dr Jan Harding, of the Centre for Science Education, studies the way girls and boys are steered into adopting different roles in life. In this "Horizon" she imagines a boy and a girl from a modern comprehensive transported into the past as victims of the scientists' experiments.

For the girl, the experiments become a recurring nightmare: no sooner is one kind of test found to be spurious than another even more bizarre ordeal is invented for her, and as each decade passes, she is surrounded by new voices of male prejudice. But perhaps the tables are about to be turned?