Direct viral infection of the developing brain can have disastrous consequences for the fetus. More subtle and perhaps more insidious are viral infections of the pregnant mother, which can have long-lasting effects such as an increased risk of schizophrenia in the offspring. A recent mouse model has shown that respiratory infection in the pregnant mother leads to marked behavioral and pharmacological abnormalities in the offspring, some of which are relevant for schizophrenia and autism. This effect on fetal brain development might be caused by the maternal antiviral immune response, possibly mediated by cytokines.