There are two ways by which a baby can come into this world: vaginally or by Cesarean delivery. Although the developmental paths that result in either vaginal or Cesarean birth a. re highly diverse and very similar at the same time, the actual indication of whether a pregnant woman has to undergo surgery is usually clear. In most cases, Cesarean deliveries are performed for obstetric, fetal, or maternal indications, some of which are considered absolute. For example, if the placenta or its vessels obscure the cervix (complete placenta previa or vasa previa, respectively), vaginal delivery would be lethal to the mother and/or her newborn. What is less clear, however, is the child’s developmental path after delivery. In particular, there is much debate on whether Cesarean delivery increases the risk of several diseases later in life, and whether any of these diseases result from a lack of exposure to the mother’s vaginal microbiota during birth.