As parents, this topic can be especially relevant since babies and children touch and eat everything in sight. Martin Blaser, MD, a professor of internal medicine at New York University told WebMD, “Most of the germs lurking about our environment and that live on our bodies are not only harmless; they’ve been with us for millennia.” Due to changes in human behavior over time, many microbes, such as those that live in the gut, are disappearing.