iStock/ThinkstockBy DR. JENNIFER ASHTON, ABC News Senior Medical Contributor

Germaphobes, listen up: A new book is encouraging parents to let their kids get dirty.

You may have already heard some say that germs can build children’s immune systems and keep them healthy. The author of Let Them Eat Dirt: Saving Your Child from an Oversanitized World adds that keeping kids too clean puts them at risk for asthma, diabetes and even obesity.

The book recommends washing hands after using the bathroom, before eating, after being with a sick person or in crowds like a mall or subway, but not after just coming in from playing outside.

Here’s my prescription: Germs are everywhere, and bacteria aren’t always bad for us. Having diverse bacterial environments on and inside our bodies is actually good for us.

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