Temporal development of the gut microbiome in early childhood from the TEDDY study.

Order of authorship in the original publication: Stewart, Ajami, O'Brien....This study confirmed that "breastfeeding was associated with higher levels of Bididofacterium species" (a very desirable organism), and that "infants delivered vaginally had higher levels of Bacteroides species" (another common and very desirable/healthy microbe). 

(Thanks to Juan Weiss for this reference and its interpretation.)