We live in an increasingly sterile world where it seems that, at every moment, we are bombarded with advertisements for cleaning products to make our lives cleaner. Whereas good old soap used to be sufficient for most of our cleaning needs, today we have an assortment of antibacterial soaps and detergents to strip away the dirt. But new studies are showing that our lack of good clean dirt, as it were, may be taking a toll on our health. A Finnish study, for example, shows that babies who were raised in homes with dogs got sick less often. As the theory goes, we need to be exposed to germs in order to be healthy.

The study followed almost 400 Finnish children from their third trimester in the womb through their first 12 months of life, and had parents fill out weekly questionnaires about their children’s contact with cats and dogs. Children who had greater contact with dogs had fewer respiratory tract infections and ear infections, and needed fewer courses of antibiotics than children who did not live with a household pet. Cats also contributed a protective effect, though not to the same extent as dogs. Several recent studies have shown that early exposure to dogs can protect some children against developing asthma and allergies.

One hypothesis is that because dogs track dirt and microbes from the outside into the house, children are exposed to a greater diversity of germs, which has a protective effect on the immune system. Dogs that spent more time outdoors seemed to contribute a greater benefit to the babies in the home. By being exposed to a wide variety of bacteria, children are also exposed to “good” bacteria, which mingle with bacteria in the intestines and help to protect against infections and allergies.

However, researchers caution against bringing a new pet into the home just so a child can be exposed to the germs. For a dog to have a beneficial effect on a child’s health, exposure has to happen very early, and not every child has the same response — some may benefit more than others. In addition, it would be a terrible idea to bring a pet into the home if a child already shows symptoms of asthma or allergies.

What the study does teach us, however, is that we don’t need to be so obsessed with cleanliness. In many ways, a little good clean dirt won’t hurt your children, and it may actually grant some health benefits.