Families may face various pressures that can affect their structure or system. Family system theory describes a family as a constantly changing, self-adaptive emotional system composed of parts that influence each other. Dr. Bowen, M. formulated this theory based on human behavior to help effectively resolve psychological problems within the family unit. Families struggle with different pressures: work, unemployment, financial problems, religious issues, health problems, disability, bereavement, the consequences of divorce. Some families, such as lesbian, gay or transgender families, face stigma or social exclusion; single parents may face poverty, parenting problems or loss of contact with another parent. Pressure from friends, relatives, the media or society is familiar to most people