Prenatal and early postnatal insults increase the likelihood for neurobehavioral problems later in life. One hypothesis suggests that the pre- and postnatal periods represent sensitive periods during which exposure to adversity programs biological systems in a manner that persists and accentuates vulnerability to behavioral problems later in life. This hypothesis is predicated on pre- and/or postnatal stress influencing structural and functional plasticity of the brain and subsequent stress resilience. The piglet is an excellent model for perinatal developmental studies because it is a gyrencephalic species with brain growth and morphology similar to humans. Its gastrointestinal anatomy and physiology are comparable and in a recent study that examined the similarity of immune-related genes in humans, pigs, and rodents, the overall mean similarity to human immune-related proteins was significantly higher for pigs compared with mouse. In the piglet model we have reported profound effects of perinatal infection, postnatal nutrition, and being born small for gestational age on brain development and behavior. The later issue is particularly relevant to this symposium because protein-energy malnutrition during pregnancy is a leading cause of intrauterine growth restriction and small for gestational age births.