Mice that live their entire life in sterile conditions, such as a plastic bubble where their only contact with humans is through gloves built into the side of the container. Gnotobiotic mice are born through cesarean delivery to prevent even the natural contamination that occurs during the delivery process. The babies are removed from the mother in germ-free condition and transferred immediately to a sterile environment to serve as a tool for research of organisms in a completely controlled situation and environment.