The term epigenetic is used buy some to denote trangenerational of traits without a change in DNA sequence.Indeed,stressful life event have been shown to alter stress susceptibility in subsequent generation.male mouse pups subjected to maternal seperation display life long increase in stress susceptibility and generate offspring that display similarly enhanced stress susceptibility over several generation. Likewise male mice subjected to chronic social defect stress as adults generate offspring that are more vulnerable to social stress than the offspring of control mice.However the mechanism underlying this tran generational transmission of stress vulnerability remain control versial . Stress produces epigenetic modification particular genes in the sperm of stressed mice ,yet it is far from certain wheter such modification contribute to the diference seen in stress vulnerability.Studies of in vitro fertilization suggest that,while epigenetic change in sperm might be a small factor in transgeneration transmission of stress vulnerability much of the of the observed transmission may be behavioral with females altering their maternal care bassed on their procreation with previously stressed futher.Further work is therefore needed to understand whether and to what extent true epigenetic inheritance of stress vulnerability adds to the well-established and powerful influence of genetics of genetics and environment expusures in determining an individual's Susceptibility resilence to stress throughout life.