Autores:
  • When you're in the womb, you're in a sterile environment. When you enter the birth canal and the world, you're not. Very quickly, you have, living on the surface of your body, trillions of bacteria, literally trillion.

    "Paul Offit On The Anti-Vaccine Movement". "Science Friday" with Ira Flatow, www.npr.org. January 7, 2011.