Final answer:
A nuclear family formed when one marries and has children is known as a family of procreation. This family structure is traditionally made up of a married couple and their children, although variations now exist.
Step-by-step explanation:
The term for the nuclear family that is formed when one marries and has children is called a family of procreation. This concept is understood as the new nuclear unit established when individuals choose to marry and have their own children, thus creating the core or nucleus of their family group. The American model of the nuclear family traditionally consists of a husband, wife, and their children, which is often considered the cultural norm, but variations of this model have become more prevalent over time. Nowadays, a nuclear family might also include single-parent households, cohabitating parents, and same-sex couples, with or without children. Despite societal changes, the nuclear family still represents an important structure in our understanding of family dynamics.