The researchers found that the thee-month-olds who were most at risk for asthma — 22 in total — had much lower amounts of four specific bacterial species in their stool samples compared with kids who didn't show these symptoms. But by the time they turned a year old, the difference in gut microbe composition was much smaller. For the researchers, this result was a sign that the presence of those four microbes very early in life might have a hand in protecting kids from asthma later on.