The family and household structure has changed a lot since 18th century, mostly because of many changes in society and technology.
Before the industrialisation the family members were performing some production functions as a unit in order to provide the family with vital goods and services. This type of production is often called 'cottage industry'. As it was very difficult to provide the whole family with essential goods and services, the society was kin-based - the extended nuclear family type was dominating as well as kin-based relationships were very strong even if the relatives didn't live 'under one roof' - more people were needed so that a family could successfully perform as a production unit.
The move to the production of manufactured goods in factories changed these trends. Families didn't need to perform the functions of production unit anymore, they became units of consumption. This affected the relationships of kin-based relatives and families have become more independent from their relatives. Talcott Parsons (1951) describes this new type of family as the 'isolated' nuclear family, which was formed due to the process of industrialisation, because married couples and their children were isolated from wider kinship. Also, many men left to work on factories, and the industrial society requires family mobility - an ability to change the location of the family to meet the demand for labour force in area where it is needed. For big families with strong connections with their kin it's very difficult to perform this function. The development of technology and use of these technologies in factories made the cottage industries' businesses uncompetitive, which also made strong kinship relationships unnecessary.
The process of industrialisation caused another process - urbanisation - families became to concentrate in large urban areas rather than in small town in countryside. The large urban areas has developed because of close location of factories nearby.
The government also has developed its functions and started to offer some important services like education and healthcare, which also made wider kinship connections not so important.
The feminists, particularly Ann Oakley (1974) argue that at the times of the industrial societies women's and children's rights were neglected and the series of Acts prohibited them from working at the factories, making them dependent on men - they were restricted to home. This is when the 'traditional' family images appeared - the male bread-winner and the mother-housewife.
The further developments of family during the industrialisation process were proposed by Young and Willmott, who identified three stages of family: pre-industrial, early industrial and symmetrical. With the development of industrial societies, the difference between social levels started to grow, dividing the ruling class from the subject class. The Marxists started to develop their theories about family being shaped to fit the needs of capitalism. Young and Willmott proposed the concept of the stratified diffusion, where all the changes in family standards of the ruling class were adopted by the middle class. That's why the symmetrical family type has appeared, where men and women share their domestic responsibilities and are becoming more equal in rights and opportunities. However, the feminists, according to McMahon, have criticised this view because women still are mainly responsible for childcare and most of the housework.