Early exposure to several infectious agents has been associated with the later development of schizophrenia. Two recent studies assessed in utero or early postnatal exposure to Toxoplasma gondii. In one study of 63 individuals, who developed schizophrenia spectrum disorders, maternal sera obtained during pregnancy showed an increased risk (OR 2.61) of having IgG antibodies to T. gondii. In the other study of 71 individuals who developed schizophrenia, sera obtained shortly after birth also showed an increased risk (OR 1.79) of having IgG antibodies to T. gondii. Causal linking mechanisms are at present speculative but include possible direct effects of maternal IgG on the developing central nervous system (CNS) of the offspring. Additional studies are underway.