In this paper we attempt to define the sociological parameters of intergenerational solidarity. We argue that social cohesion between generations is influenced by affectual, associational, consensual, functional, normative, and structural factors that operate at both the macro social level of society and groups-what we call "macrogens"-and at the micro social level of families and individuals-our term is "microgens." Similarly we argue that it is impossible to discuss intergenerational solidarity without considering its opposite, conflict, and vice versa. On the basis of the evidence reviewed, it does not appear that there will be marked generational conflict in the future, and it is likely that intergenerational solidarity and altruism will remain present at high levels.