AbstractPrimiparous female mice of 2 lines genetically selected for different narcotic responses to ethanol were administered 10% (v/v) ethanol in their drinking water during Days 2–14 of lactation. Ethanol treatment resulted in a marked decrease in growth and viability of pups in both lines. Fewer offspring of the ethanol‐sensitive line survived to weaning, apparently because of the failure of a large number of dams to exhibit maternal care. The combination of ethanol treatment and an additional environmental stressor (mouse hepatic virus) had a devastating effect on maternal behavior and offspring survival in the ethanol‐sensitive line, but far less effect on the ethanol‐insensitive mice. Thus, ethanol‐sensitive animals appear to be more susceptible to a variety of stressors, includin