It seems like sense to most parents to make their baby is always in a clean place. Most parents do their best to keep dirt and away from their little . However, a scientist says dirt is an important part of making babies . Dr Jack Gilbert from the University of Chicago studies the ecosystems of bacteria. He did research into how dirt and bacteria affect children. He published his in a book called 'Dirt is Good: The Advantage of Germs for Your Child’s Developing Immune System'. He told America's NPR news that: "It's fine to wash their hands if there's a…flu going around, but if they're interacting with a dog and the dog licks their , that's not a bad ."
Dr Gilbert wrote that letting children get dirty was beneficial. Exposing small kids to dirt helps to build their immune . Dr Gilbert even argues that children often get because parents try to protect their kids too much and try too hard to clean that children use. He said parents now over-sterilize everything in the . This causes children's immune systems to become too , which can lead to things like asthma, eczema, and food allergies. Gilbert even defended the "five- rule". Many people think it is OK to eat something that fell on the floor for than five seconds. Gilbert says it is OK to eat something that fell on the floor as long as the isn't really dirty.