In the past decade, the use of assisted reproductive treatments such as in vitro fertilization and intracytoplasmatic sperm injection has consistently increased, with approximately 1% of infants born in 2004 being conceived through such treatments. As well, there is accumulating evidence suggesting that there may be a relationship between the use of assisted reproductive treatments and autism spectrum disorders (ASDs) in children born as the result of such treatments. This raises the possibility that the apparent rise in the prevalence of ASDs in the past decades could be due in part to the increasing use of infertility treatments in Western societies. This potential link has not been rigorously examined by scientists, and the use of population-based health registers provides an opportunity test this hypothesis. In the present study, researchers will use population-based health records collected in Sweden for all infants born between 1982 and 2001, including those born after assisted reproduction treatments. Dr. Reichenberg and colleagues will analyze the data to determine whether diagnoses of ASDs link to the use of assisted reproductive treatments, as well as to other potentially relevant factors such as parental age and perinatal indices such as birthweight. This research may provide a better understand of pre-pregnancy and prenatal factors that affect the risk of developing ASDs.