Society needs to regulate sexual activity. The nuclear family regulates a married couple's sexual behaviour and helps to maintain their relationship.
The reproductive function
Society needs new members if it is to survive over time. The nuclear family produces the next generation of society's members.
The economic function
Society needs a way of providing people with financial support (for instance, food and shelter). Economic cooperation is based on a division of labour between the husband and wife within the nuclear family.
The educational function
society needs to ensure that new members learn its culture. This learning takes place through socialisation within the nuclear family.