For the last decade or two, people have been looking for something to attribute to the increase in the number of people with allergies and autoimmune diseases. A lot of ideas have been floated around - cell phones, vaccines, hand sanitizers or anything else that we use more now than we did 20 years ago.
On that list is also the increase of births done by Cesarean section.
The hypothesis is that babies born by Cesarean have a different microbiome (or set of bacteria) on them than those born vaginally. And, that those bacteria that are first to establish themselves in the newborn impact the health of the baby for the rest of their life.
The idea that has taken hold is that babies born by Cesarean section are missing exposure to important microbes because they do...