Fetal Alcohol Spectrum Disorders is an important cause of intellectual and other developmental disabilities, both in the US and worldwide. This seminar will focus on the epidemiology of FASD and its consequences for human development and adult health. The 1st to 2nd trimester period is a particularly important period of vulnerability, because during this period, neural stem cells produce most of the neurons of the adult brain. Mechanisms of brain vulnerability will be discussed with specific reference to a class of regulatory small RNAs, microRNAs. Finally, strategies for early diagnosis will be discussed with a view to providing opportunities for early intervention.