“The microbiome can shape the developing brain in multiple ways,” John Lukens, lead researcher and PhD student from the University of Virginia School of Medicine, said in a statement.

“The microbiome is really important to the calibration of how the offspring’s immune system is going to respond to an infection or injury or stress.”

As for autism, this link may come down to a particular molecule called interleukin-17a (or IL-17a), which is produced by the immune system.