We are changing our concept that the newborn infant emerges from a sterile environment. In-
utero colonization may have major impacts on the developing mammal in terms of
development of immunity and metabolism that, with epigenetic modifications, will lead to
diseases in later life. In addition, the microbial profile that develops during and after birth
depends on mode of delivery, type of feeding (human milk versus formula) and various other
environmental factors to which the newborn is exposed. The goal of this review is to clarify …