In the United States, one of the biggest changes in families in the last century has been a decrease in the number of extended families. One very important reason for this decrease was industrialization. The growth of industry made it possible for many young people to leave their families and move to the city to work in factories By the 1920s, a majority of children in the United States were no longer living in extended families. Instead, they were living in families with a father who went to work and a mother who stayed at home.