Two to 5 per cent of children will experience and seizure with fever by the time they reach their 6th birthday. Past studies have suggested that children who have a febrile seizure have four times the risk of developing epilepsy than children without a febrile seizure. In addition, some studies have found delays in intellectual development and behavior among children with a febrile seizure, while others have found no delay. Some researchers believe that febrile seizures cause brain abnormalities that may then later cause epilepsy or developmental delays. Other researchers believe that some children have brain abnormalities that make them more susceptible to having a seizure when they have a fever. From our study we seek to learn in what way children with first febrile seizure with a brain abnormality are different from those with first febrile seizure and no brain abnormality, and how both these groups differ from children who have an illness with a fever over 101 degrees but do not have a seizure. The outcomes we will consider are type of febrile seizure, family history of febrile seizure, developmental delays in intellect and behavior, and recurrence of febrile seizure. We will recruit study subjects from the Pediatric Emergency Department at CPMC. All our study subjects will be children between the ages of 6 months and 5 years. The case group will be composed of children with a first febrile seizure (i.e., a seizure of any type). The comparison group will be composed of children with a fever of at least 101 degrees, no associated seizure, no CNS infection, and no seizure history.