Narrator: Pets may not be good for the new carpet, but there's a growing body of evidence that exposure to animals could be good for your child's immune system…
Michael Smith, MD: Traditionally years ago we felt that people who had pets especially as a young kid that actually developed more allergies, recent research has actually shown that not to be true,and kids who grow up in households with pets, cats and dogs actually have fewer allergies as they get older.
Narrator: It's all part of what's called the 'hygiene hypothesis'—the theory that the more 'nasties' we expose ourselves to, the more resilient we become.The idea is gaining popularity because in spite of what some may view as a fanatic trend toward staying clean and germ free, incidences of allergies are actually on the rise.
Kathleen Sheerin, MD: So we're not letting the immune system be exposed to the germs that in the days of our grandparents happened all the time.
Narrator: Research shows routine exposure to two or more pets over the first few years of life had the most dramatic impact on a child's defenses:
Michael Smith, MD: Once we develop school age the immune system is probably too far along to have too much of an impact. So we think probably the younger the better.
Narrator: Will early pet exposure work for asthmatics? Unfortunately, studies do not show any benefit, but researchers continue to investigate …
Kathleen Sheerin, MD: In Germany they did a study on a dairy farm and these kids actually did great because they played with the cows, and the incidence of asthma and allergies in those kids were extremely low.
Narrator: Before you turn your house into a barn, keep in mind that many allergies are hereditary and early exposure may not be advisable.Not to mention exposure can still wreak havoc for the adult members of a household.
Kathleen Sheerin, MD: Well the parent may end up having to move out because they can't cohabitate with a cat or a dog in their house. So it's not necessarily a practical solution.
Narrator: Experts stress that while you're letting your kids hug and kiss their furry pals,you should remain vigilant about good hygiene—still thought to be a major reason life-expectancy has increased so dramatically over the past century in the developed world.For WebMD, I'm Damon Meharg.