It is for parents to make sure their baby is always . Parents do their to keep dirt away from babies. A scientist says dirt is because it makes babies . Dr Jack Gilbert did research into how dirt affects children. His is in a called 'Dirt is Good: The Advantage of Germs for Your Child’s Developing Immune System'. He said: "It's to wash their hands….but if a licks their face, that's not a bad ."
Dr Gilbert said letting get dirty was good. The dirt helps to build their immune . Children often get allergies because parents clean that children use. This makes children's immune weaker, which can cause and food allergies. Gilbert said the "five- rule" is OK. This is when you eat something that fell on the for fewer than five . Gilbert says it is OK if the floor isn't dirty.