A new study published in *The Journal of Immunology* suggests a strong link between a mother’s gut microbiota and the development of autism in offspring. “The microbiome can shape the developing brain in multiple ways,” said lead researcher John Lukens from the University of Virginia.

The key focus is on a molecule called interleukin-17a (IL-17a), produced by the immune system. IL-17a, already linked to diseases like psoriasis and multiple sclerosis, can also influence brain development in the womb.

To test this, researchers used mice with different gut microbiota. The first group had microbiota that triggered strong IL-17a responses; the second group did not. When IL-17a was suppressed, all offspring showed normal behavior. But when left untreated, pups from the first group developed autism-like symptoms.

To confirm the microbiota’s role, scientists transplanted feces from the first group into the second. As predicted, the second group’s pups developed similar neurological symptoms.

Although it’s early research, the findings suggest that a mother’s gut health may influence autism risk. Lukens said, “IL-17a might be a single component in a much bigger picture,” and hopes to find similar patterns in humans next.