Is the cleanliness theory completely discounted now? It's not mentioned in the article. The idea is that there are so few pathogens in the environment during childhood so the immune system can't tune itself. So then it reacts out of proportion to some trigger substances which then form the basis of the allergy.
When did it get discounted? I thought there was a reasonable amount of evidence supporting it (at least the last pop-science TV show I watched on the subject suggested that).
