In recent years, doctors have begun to give parents some surprising advice about preventing allergies and asthma in children: let them cuddle up to family pets during the first year of life. The idea, supported by several studies, is to expose the infants to the microbes that make their home in animal fur. That would prime the baby's immune system, still under construction, to recognize common allergens as harmless and not to mount the sneezing, wheezing and red-eyed response.
Researchers from the Medical College of Georgia recently offered more evidence of that effect but added a caveat. Their research, presented...