Dog’s status as man’s best friend may begin before the human half of that duo is even born.

When there’s a furry pet in the home during a woman’s pregnancy, and especially when a dog or cat is present after the baby is born, the child has more diverse gut bacteria that can protect against allergies and obesity, a new study has shown.

Researchers at the University of Alberta assessed the microbes in the guts of nearly 800 Canadian infants by analyzing fecal samples collected when the babies were 3 or 4 months old. In results published in the journal Microbiome, the team found children exposed to pets, mostly dogs, had markedly higher levels of two beneficial bacterial strains than kids in homes without such companions. One strain is associated with reduced risk of allergies, while the other is linked to decreased obesity risk.

The researchers explained that the bacteria associated with a cat or dog living in a home inevitably become mingled with the environment, increasing the variety of microorganisms a child encounters regularly. This can lead to changes in the bacterial population of the gut.

Researchers noted that even if a pet is put up for adoption before the baby arrives, its past presence changes the variety of bacteria in household dust.

The study follows previous research that shows exposure to dirt and bacteria can help children build up immunity, and that kids who grow up with pets have lower allergy and asthma rates.

It just goes to show that having a pet at a young age can help a child for the rest of his or her life.