Over the past few years, more and more research has been published revealing just how fundamental our gut microbiome is to our health. It can affect everything from our response to fear and negative stimuli, to our weight and mental health, to whether or not we develop autoimmune diseases such as lupus and type 1 diabetes.

Now, a new study published in The Journal of Immunology has found a link between the gut microbiome and the neurodevelopmental condition autism using animal studies. However, it is not our own microbiome that affects whether or not we develop autism, the researchers say – it’s our mom’s.

“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. The molecule has already been associated with conditions like rheumatoid arthritis, multiple sclerosis, and psoriasis, and has been shown to serve an important role in preventing infections, notably those of the fungal kind. Importantly, it can also influence the way the brain develops in the womb.