If you have a child, you'll read about this. A baby's digestive system is essentially sterile in the womb. There's increasing evidence that important bacteria a

If you have a child, you'll read about this. A baby's digestive system is essentially sterile in the womb. There's increasing evidence that important bacteria are passed to the newborn from the vaginal canal during the birthing process – and is an argument against C-sections. Also related is the resurgent practice of placing a newborn directly against the mother's bare chest immediately after birth, which among other benefits, is supposed to foster bacterial transference through skin-to-skin contact. As a disclaimer, I'll just say that this field of knowledge seems rife with theories but somewhat lacking credible scientific studies that do long-term tracking of health outcomes. So, I take much of it with a grain of salt. Here are a couple of studies I found: Delivery mode shapes the acquisition and structure of the initial microbiota across multiple body habitats in newborns http://www.pnas.org/content/107/26/11971.full http://www.pnas.org/content/107/26/11971.full Influence of mode of delivery on gut microbiota composition in seven year old children http://gut.bmj.com/content/53/9/1388.2.long http://gut.bmj.com/content/53/9/1388.2.long