Give us this day our daily germs.

Are we sparing the dirt and spoiling our children's immune systems? The theory that some germs are necessary in developing healthy immune systems is gaining credence as more evidence emerges. It is vital that we find out which germs are needed, when and how, before the increase in diseases attributable to faulty regulation of the immune system (allergies, autoimmunity, inflammatory bowel disease) spirals out of control.