Family is coined by our society to consist of parents and their children. Based on our modern day families, we now have couples with no children, couples that form with children from previous marriages, gay couples, etc. People want to belong, they have a need to identify with others when their "family" at home is broken. We also come to realize that our family unit can be viewed differently in our society. For instance, gangs consider other members their "family." I don't believe there is a such thing as "normal" family. We all want to belong to a group to feel like we are contributing to our society, whether that be through a "normal" family or a more modern day version of family.
