The second you become a parent, you probably feel like you have to coat your entire world in hand sanitizer – and depending on what your child likes to get into when your back is turned, washing away germs can be a tricky task. Fortunately, you don't have to worry; Dr. Mattke of Mayo Clinic Children's Center says that "early exposure to their environment full of germs, bacteria and viruses is not a bad thing." It can actually help strengthen their immune system and may help prevent noninfectious conditions like asthma and allergies. So the next time you catch your child playing in the mud or licking their dirty hands, know that it's not the end of the world. Just make sure you know how to manage good vs. bad bacteria.