Doctor: People who have grown up on farms and have been frequently exposed to germs...

Whether farm animals exposed to microorganisms can develop allergies as a result

To which species of microorganisms children who grow up on farms are most often exposed

How the lifestyles of children on farms tend to be distinctive in other ways known to affect the function of the immune system

Whether adults who work with farm animals are less likely to develop allergies than adults from similar backgrounds who work in sanitary environments

Whether most of the allergies suffered by adults who did not grow up on farms are caused by allergens found on farms