Family is defined as “two or more persons related by blood, marriage or adoption who reside together” (Schiffman and Kanuk 2007, 346). “In a more dynamic sense, the individuals who constitute a family might be described as members of the most basic social group who live together and interact to satisfy their personal and mutual needs” (Schiffman and Kanuk 2007, 346-347). Therefore, not only do we have to study and do research about individual consumers but we also have to consider groups of people such as families and the influence of their members on others within the group. “Today in the United States, 68 percent of the 111.3 million household are families. According to many sources, the family remains the central or dominant institution in providing for the welfare of its members and is the major household consumer and consuming unit” (Schiffman and Kanuk 2007, 347). This means the family is a notable consuming unit if not the most important one. “Although families sometimes are referred to as households, not all households are families. For example, a household might include individuals who are not related by blood, marriage, or adoption, such as unmarried couples, family friends, roommates or boarders. However, within the context of consumer behavior households and families usually are treated as synonymous, and we will continue this convention” (Schiffman and Kanuk 2007, 347). Consequently, groups of people who interact to accomplish either individual or mutual goals may be considered as a unique consuming unit even if they are not related by blood, marriage or adoption. Thus, The research process would be the same. Families can be divided in three main types: the married couples, the nuclear family and the extended family.