A set of environmental influences that are the same for members of related pairs (e.g., parents and children, siblings). There are two classes of general environmental influences: “general family environment” – characterized by common parameters for all family members (socio-economic status of the family, level of education of parents, housing conditions, family traditions and customs, religious beliefs, etc.); “family environment” is specific to specific pairs of family members (twins, siblings, parent-child environment, etc.), it is an environment common only to members of a given dyad.