Nuclear family - a family unit consisting of two adults and any number of children living together. The children might be biological, step or adopted.
Extended family - grandparents, aunts, uncles, and cousins, either all living nearby or within the same household. For example, if a married couple lives with either the husband or wife's parents the family changes from a nuclear to extended household.
Reconstituted family - also known as a step family. A family where one or both adults have children from previous relationships living with them.
Single parent family - consists of a parent not living with a partner, who has most of the day-to-day responsibilities for raising the children. The children will live with this single parent for the majority of the time, but they may still have contact with their other parent.
Same-sex family - since civil partnerships were legalised in 2005, the number of same sex families has been growing (same-sex marriage was legalised in 2014). Same-sex couples cannot conceive together, so their children may be adopted or be the biological children of one member of the couple. They may also be from a sperm donor or a surrogate birth mother.