This has been hypothesised for a while and is listed in many pregnancy books. There are also hypothesis linking the difference in gut flora to other long term o

This has been hypothesised for a while and is listed in many pregnancy books. There are also hypothesis linking the difference in gut flora to other long term outcomes (obesity, autism etc) in adults. Reference: J. Neu and J. Rushing, “Cesarean Versus Vaginal Delivery: Long-Term Infant Outcomes and the Hygiene Hypothesis,” Clinics in Perinatology 38, no. 2 (2011): 321–331.