One of the most popular of the Just William stories tells how William and his Outlaw friends were joined one day by the cherished and sheltered Violet Elizabeth Bott. Violet Elizabeth had a burning desire to take part in ''boy's games''. As a result she had a wonderful time in the woods but ended up completely unrecognisable by her family.
Western society does not expect little girls to play in the dirt and get messy. Ribbons and curls tend to be more in line of what is expected of them, but writing in the US journal Social Science & Medicine, Dr Sharyn Clough, from the Department of Philosophy at Oregon State University puts forward the view that this emphasis on cleanliness may contribute to higher rates of certain diseases in adult women.
There is a well-documented link between increased hygiene and sanitation and higher rates of asthma, allergies and autoimmune disorders that is known as ''hygiene hypothesis''. Dr Clough points out that women have higher rates in all of these disorders and she thinks she knows the reason why.
''Girls,'' she says, ''tend to be dressed more in clothing that is not supposed to get dirty, they tend to play indoors more than boys and their playtime is more often supervised by parents. As a result girls stay cleaner.'' She points out that there is a significant difference in the types and amounts of germs that boys and girls are exposed to, leading her to the view that this might explain some of the health differences between men and women.
Dr Clough proposes that there should be new ways of looking at old studies. The ''hygiene hypothesis'' has linked the recent rise in asthma, allergies and autoimmune disorders such as Crohn's disease and rheumatoid arthritis with particular geographical and environmental locations. Many studies have noted that as countries become industrialised and more urban, rates of these diseases rise. A good example is India, where rates of Crohn's disease are climbing as sanitation improves and industrialisation increases.
In the United States it is reported that asthma prevalence is 8.9% in females as opposed to 6.5% in males and autoimmune diseases strike three times as many women as men. The rate for multiple sclerosis for women is double that for men and three women suffer from rheumatoid arthritis to every man. With the disease lupus, nine times as many women are affected as men. And so it goes on.
Dr Clough is a philosopher of science and epistemology whose particular field is feminist theory and gender differences. The focus of her work is to study scientific research and look for the implicit or hidden assumptions that guide that research. She believes that the link between hygiene, gender and disease is not just a fluke.
While she does not advocate feeding little girls with spoonfuls of dirt, she does agree with the health experts who say that boys and girls should spend more time outdoors, even if they do get a little dirty.