It is important to note that functionalism currently has the role of 'straw man' within sociology; you build it up to knock it down. It is clear that functionalism does have its faults, but equally, its decline can be seen in part as a consequence of fashion change.
Until the 1960s, functionalism was the dominant sociological perspective. Indeed, many of the central concepts used by all sociologists derive from the functionalist tradition, for example, norms, values, socialisation, status, role. In other words, be careful to consider functionalism on its merits - its not all bad! Functionalist assumptions concerning families have, however, been subject to sustained criticism.
The bedrock of functionalism is that if a social institution exists, then it must have, or once have had, a purpose. That is, institutions meet social needs. Consequently, functionalists have produced lists of the functions that the family carries out for the benefit of both society and the individuals within families.
Unfortunately, the lists of functions produced are, themselves, examples of hope and ideals rather than empirically grounded assertions.
Traditionally, these functions have been divided into 'essential' and 'non-essential'. It is argued that the non-essential functions have been abandoned in contemporary industrial societies because other institutions have been created to take over these tasks.
This idea of the shedding of tasks and of increasing specialisation is central to the functionalist notion of the division of labour and the coming of industrial society. This specialisation is known as differentiation.
Who knows what is essential or non-essential?
Why assume these essential functions cannot be achieved in some other way?
Were the non-essential functions really once carried out by the family?
The essential function of the family for society is pattern maintenance. For individuals, the essential function is the stabilisation of the adult personality and the socialisation of children. Some would add the provision of a home.
The history of the family is seen as evolutionary, and this evolution takes the form of adaptation by the family to processes of social change. Note: the family is seen as adapting to change rather than as a cause of wider social change.
The contemporary western family, 'the' family form, is seen as nuclear and living in isolation from wider kin, and that this form emerged so as to achieve a 'fit' between family form and industrial society. Note: the tendency, particularly in functionalist accounts, is to talk of 'the' family, rather than families.
Functionalists argue that the family is a universal social institution, founded on biological attributes and that gender roles within families are the result of such attributes. The biological attributes of the adult members of a nuclear family give rise to two leaders; the instrumental leader and the affective leader.