Study: Infant health not dogged by pets

Fido the dog and Ginger the cat need not worry about being replaced by a new baby: in fact, they could be helping parents raise healthier children.

A new study finds that children who lived with dogs or cats during their first year of life got sick less frequently than kids from pet-free zones. The study, published yesterday in the journal Pediatrics, provides evidence for the counterintuitive notion that an overly clean environment may not be ideal for babies.

Sharing a home with a pet may be an early form of cross-training for the body's defense systems. Studies also suggest that the dirt and microbes brought indoors by pets could bolster communities of helpful bacteria, yeast and other microscopic creatures that live in a developing child's body.

For the new study, researchers tracked the health of 397 Finnish children born between September 2002 and May 2005. When the infants were 9 weeks old, parents began keeping weekly diaries to document indicators of their children's health, including runny noses, coughs and ear infections. Parents noted when their babies were given antibiotics.

The researchers found that cats and dogs were linked to a reduced incidence of various types of illness. The effect was stronger for dogs than for cats: Babies who lived with dogs were 31 percent more likely to be in good health than their counterparts who didn't, and babies with cats had a 6 percent advantage over those without feline family members.