uclear family is a term used to define a family group consisting of a pair of adults and their children. This is in contrast to the smaller single-parent family, and to the larger extended family. Nuclear families typically center on a married couple, but not always;[1] the nuclear family may have any number of children. There are differences in definition among observers; some definitions allow only biological children that are full-blood siblings,[2] while others allow for a stepparent and any mix of dependent children including stepchildren and adopted children.[3][4]
Families structures of a single married couple and their children were