"The assumption that it is the men who should be warriors seems to be almost universal through time and across cultures and, while there are examples of women warriors, the overwhelming majority of those who have fought are men. And when rules of war have developed in different societies, women, along with old people, children and, sometimes, priests have been classified as non-combatants. The reasons why men have largely done the fighting and women have not are as much debated as the origins of war itself, and again the explanations range from the biological to the cultural. If gender differences are averaged, men come out higher on the scale of strength and size and possibly aggression, but there are many big strong women who can match and surpass men. The fact that men have more testosterone than women may make them more prone to being aggressive – although scientists are far from reaching a consensus – but there are many men who are gentle by nature and do not want to fight. Militaristic societies such as Sparta or the military through the ages would not have spent so much time on training which inculcates the ‘right’ attitudes if the great majority of men were natural-born killers. Women, when they choose or are obliged to fight, can be as fierce as men."