Nuclear and extended families A husband and wife and their children are called a nuclear family.It may include grandparents, uncles, aunts, and cousins.5s This is the typical family unit in most Western countries.In many other parts of the world, however, it is more typical for the extended family to live together in one household.In cultures where the nuclear family is the typical unit, children usually leave home in their early twenties, often before they get married.Increasingly, young people are moving back to their parents' homes after they graduate from college.