·In utero IgG transfer decreased the disease severity in BALB/c offspring. · Offspring of FcRn-deficient dam nursed by OVA-fed C57BL/6 WT dams showed protective effects against OVA-induced asthma-like symptom. · Anti-IFN-γ treatment of offspring during sensitization and challenge with allergen abolished the protection. Here, IFNG is linked to asthma.