Which family structure is characterized by having both biological parents present?

The nuclear family structure is defined as a family unit consisting of two parents and their biological or adopted children living together in a single household. This configuration emphasizes the presence of both biological parents, typically a mother and father, who are directly responsible for the upbringing of their children. The nuclear family is often viewed as the traditional family model in many societies, focusing on the immediate family rather than a broader familial network.

In contrast, a single-parent family is led by one adult raising one or more children, an extended family includes other relatives beyond the immediate parents and children, and a blended family is formed when one or both partners in a relationship have children from previous partnerships, creating a family that combines children from these different relationships. Thus, the key distinction of the nuclear family is the partnership of both biological parents living together with their children.