Infants who are delivered by cesarean section (C-section) have a microbiota that resembles the skin microbiota from their mothers, which contrasts to vaginally delivered infants, who harbour microbial communities that resemble those from the maternal vagina. As delivery by C-section has been associated with an increased risk of immune and metabolic disorders, which are thought to arise owing to changes in the microbiota, Dominguez-Bello et al. tested whether exposure of C-section-delivered newborns to the maternal vaginal fluid at birth could restore the microbiota. The authors analysed four infants who were swabbed with vaginal fluid from their mothers within the first two minutes after birth and observed that their microbiome composition resembled the microbiome of vaginally delivered infants throughout the first month of life.