Spit-Cleaned Pacifiers Boost Babies' Immune Systems Discover Magazine (blog) It's known as the hygiene hypothesis, and it states that, without exposure to a wide array of germs, our immune systems won't learn to distinguish our own cells from harmful invaders. Having a healthy amount of germs on our hands, toys, and, yes …
More here:
Spit-Cleaned Pacifiers Boost Babies’ Immune Systems – Discover Magazine (blog)