The prevalence of autism, a neurodevelopmental condition resulting from genetic and environmental causes, has increased dramatically during the last decade. Among the potential environmental factors, hyperserotonemia during pregnancy and its effect on brain development could be playing a role in this prevalence raise. In the rodent model developed by Whitaker-Azmitia and colleagues, hyperserotonemia during fetal development results in a dysfunction of the hypothalamo-pituitary axis, affecting the amygdala as well as pro-social hormone oxytocin regulation.