Primary Socialization is socialization carried out by the immediate family. Primary socialization occurs as parents teach their children the basic "rules" of society, impart basic role templates, and implant the basic archetypes. Within the current system, primary socialization includes gender and labor expectations, the role of authority and punishment, ideas about the purpose of existence, place in society, and so on.
In modern society, socialization is handled primarily by the mother. This is, however, neither a natural nor an optimal arrangement. Optimally, both parents would be involved in primary socialization and these parents would be assisted by a heavily funded support networks designed to assist parents and encourage proper development of the physical unit. Obviously, the current productive organization of this planet precludes optimal primary socialization.