Variations in maternal care over the first week of life alter the expression of genes encoding for various subunits of the GABA(A)/benzodiazepine (BZ) receptor in the amygdala, a brain region associated with fear behavior. Increased maternal licking/grooming and arched-back nursing are associated with decreased fearfulness and enhanced expression of the subunits that confer BZ sensitivity. In these studies we found that the offspring of high licking/grooming-arched-back nursing mothers also showed increased behavioral sensitivity to acute BZ treatment, suggesting a functional relation between the effect on gene expression and fear behavior.