The present invention provides a method for reducing the risk of developing a psychiatric disorder (e.g., ASD, of which autism is a particular example) in a fetus comprising administering an inhibitor of T helper 17 (Th17) cell activity to the mother of the fetus, while the mother is pregnant with the fetus. The invention further relates to the use and application of compounds or agents that inhibit Th17 activity or that inhibit IL-17a or IL-17 signaling for reducing fetal risk for developing a psychiatric disorder. The invention relates to compounds or agents that inhibit Th17 activity or that inhibit IL-17a for reducing fetal risk for developing a psychiatric disorder, such as ASD, and use of such compounds or agents in the preparation of a medicament for reducing fetal risk for developing a psychiatric disorder.
