The effects of age, gender, and family background on children's use of prescription psychoactive medications were studied. Patient and prescribing information was obtained for children enrolled as dependents in any of five prescription drug benefit plans during the period from December 29, 1992, through December 28, 1993. A binary response model was specified under the assumption of logistic distribution of probabilities of psychotropic drug use. The independent variables were family size, parenting type (single- or two-parent family), parental use of psychotropic medications, and child's age, gender, and the interaction between age and gender. Logistic regression analysis was conducted not only for overall psychotropic drug use but also for antidepressants, antianxiety drugs, and CNS stimulants. The sample included 3144 children; 3.9% received psychotropic drugs. Family size and parenting type had no effect on overall use of psychotropic drugs by children, but children were more likely to receive psychotropic drugs if the parents took them. The study showed an interaction between age and gender. At younger ages, boys were more likely than girls to receive psychotropic drugs; the opposite was true at older ages. For particular subcategories of drugs the study showed that (1) boys were more likely than girls, and young children were more likely than older children, to receive CNS stimulants, (2) children from single-parent families were less likely to use antidepressants than children from two-parent households, and (3) the influence of mothers' psychotropic drug use extended to all three drug classes, but the influence of fathers' psychotropic drug use existed for antidepressants only. The effects of demographic and familial factors on children's use of psychotropic drugs varied according to the drug class.