Cocaine hydrochloride (0 to 30 mg/kg, s.c.) was administered daily for a minimum of 72 days to Long Evans rats. Animals receiving the lower doses were pair fed to animals receiving the higher dose. Males were bred to untreated females. Paternal cocaine administration did not affect litter size, birth weight, or weight at weaning, but did result in offspring hyperactivity. A similar study was conducted for paternal alcohol consumption in Long Evans rats. Males consumed alcohol (35%, 17.5% or 0% ethanol derived calories) for 8 to 9 weeks and were then bred to untreated females. Males consuming the lower concentrations were pair fed to 35% EDC animals. Paternal alcohol consumption did not affect birth weight or weight at weaning but resulted in offspring hypoactivity. Mice sired by alcohol-consuming males were also hypoactive.