Family structure has varied widely throughout time. One aspect of a society that could be looked at as having a large impact on the way its people structure their families is the economy. While economies are dependent on the time period and culture that you’re looking at, some trends can still be seen.
Back when a lot of cultures economies were based around trading and hunting and gathering for food the lines between families were sort of blurred. There was more or less a head of the village and everyone took part in raising the children and other familial duties. It was more of a community unit than a community made up of family units like it is in our society.
Then with the creation of money, people began being able to amass wealth, which led to people becoming more selfish and looking after themselves and their family instead of everyone in the community and this is when we begin to see how the economy really shapes family structure.
When the economy is based on farming, large families are needed so you can have more workers tending to the animals and/or crops. This led to large nuclear families with one couple having lots of children.
As time went on, jobs shifted from agriculture to more industrial and professional jobs that did not allow children to work. This completely changed family structures. Families began having less and less children because now, instead of just costing money, your children were no longer helping you make any money. Also, the majority of the pressure to provide for the family was originally placed on the father as the mother would most likely be a stay at home mom. Families during this time typically had the father as the head and the mother was more of a support figure.
Then, the economy had another transformation and women began working too. This took some of the legitimacy for male dominance away and shared it with women. Now, not only do we see families being led jointly by mom and dad. Today you may see, or even be a part of, a family where the mom is the head and the dad plays more of a supportive role. My family was like this. My dad had a period or two where he was without work and that led to my mom being the main breadwinner and she also was more of the authoritarian around the home.
As one can easily tell, the way a family is structured is heavily dependent on how that societies economy is set up. Who is responsible for carrying the brunt of the financial burden that comes along with a family is usually deemed the head of the family. Also, the way in which the economy is set up on a macro level helps determine the size and shape of the family unit and could even be used to draw the lines between who is family and who is not as is the case with some people living with just their nuclear families and others cohabitate with their extended families and include aunts, uncles, cousins and grandparents as well.