There’s lots of cool/gross stuff in this Michael Pollan article about the microbes in human bodies: “for every human cell that is intrinsic to our body, there are about 10 resident microbes,” mother’s milk feeds newborns’ “gut bugs,” and there are “gnotobiotic mice” without any germs.
Owners of small bathrooms will probably want to skip the part about how far away you should keep your toothbrush from your toilet.