How do you create a germ-free mouse? YONG: You raise them in the sterile isolators, these plastic bubbles that are completely disconnected from the microbial world. The mice are the only things living inside them. They have sterile food, sterile water. Anything that's put in gets sterilized before it's connected to these chambers. And I think that makes these mice some of the strangest animals on the planet. I visited one of the facilities that raises them. And I held one not with my bare hands but with this black rubber glove that protrudes into their plastic bubble. And this is an animal that, unlike anything else - unlike you or me or an elephant or an - anything - has no microbe. It's like a silhouette that hasn't been filled in yet. And because of that, it has a lot of problems. It has different - it has problems with its bones, its blood vessels, its gut, its behavior. It testifies, I think, to just how important microbes are for sculpting and shaping our bodies and how much can go wrong if we live our lives in their absence. - http://www.npr.org/2016/08/18/490432969/eating-yogurt-is-not-enough-rebalancing-the-ecosystem-of-the-microbes-within-us