Concepts of Family purely in terms of sharing a household, a collection of individuals living together. Others define the family based on kinship. A family is a group of people who share common ancestors or a basic social unit comprised of parents and their children. Still, there are several characteristics that are generally identified with a well-functioning family which includes support; love and caring for other family members; providing security and a sense of belonging; open communication; making each person within the family feel important, valued, respected and esteemed. Family members are often close and feel they can depend on one another for caring guidance and support. Whether it's grandparents, aunts and uncles or even close friends who make up a family, what is important is the love or common interests that bind them together. The key elements of a family system are its members, beliefs, roles, rules, assets, limitations, goals, boundaries, subsystems (e.g. siblings), environment - a larger system of systems, or metasystem. Family Systems Theory Definition. The family systems theory states that a family functions as a system wherein each member plays a specific role and must follow certain rules. Based on the roles within the system, people are expected to interact with and respond to one another in a certain way. several types of family systems: nuclear family, matrifocal families, extended families, and blended families etc.