Compared with their male counterparts, females with schizophrenia, on average, show better premorbid functioning, later onset, and a more benign course of illness. They are also more likely to have a family history of schizophrenia and/or affective illness, to exhibit “atypical” and affective features, and to show a seasonal pattern of hospital admission that mimics that of patients with mania. However, there exists a paradox. Although schizophrenia in females has much in common with affective disorder, the “schizophrenogenic” effect of maternal influenza also appears to be more significant in female than in male schizophrenia. Perhaps females with a predisposition to affective psychosis who have also been subject to the effects of maternal viral infection during gestation develop some subtle neurodevelopmental damage that renders their psychosis schizophrenia-like.