Bugwars: see this Nature article from 2019: C-section babies are missing key microbes : How a baby is born has a profound impact on their microbiome — the community of microbes that colonize the body. That’s the finding of the largest ever study of the newborn microbiome, which offers the strongest evidence yet that children born through the vaginal canal carry different microbes from those delivered by caesarean section. Newborns delivered by c-section, the study found, tend to lack strains of gut bacteria found in healthy children and adults. Instead, their guts harbour harmful microbes that are common in hospitals. The study, which analysed nearly 600 births in the United Kingdom, did not look at whether these microbial differences can affect health later in life. But the presence of disease-causing bacteria is a concern, says Trevor Lawley, a microbiologist at the Wellcome Sanger Institute in Hinxton, UK, who led the work1, published in Nature on 18 September. “The level of co...