According to structural-functional analysis, society defines gender based on the functions individuals perform.

According to structural-functional analysis, the concept of gender is understood in terms of the social and economic roles that individuals fulfill within a society. This approach views society as a complex system whose parts work together to promote solidarity and stability. It implies that various social institutions and processes in society exist to serve some important functions to help maintain the stability and continuity of that society.

In terms of gender, structural-functional analysis suggests that society assigns different roles to men and women based on what is seen as best suited for maintaining social order. For example, in traditional views, men might be ascribed the role of breadwinner, going out to work and providing for the family, while women might be ascribed the role of homemaker, responsible for maintaining the home and raising children. According to this perspective, these gender roles stem from the natural differences between men and women and are reinforced by social institutions such as family, education, and religion.

These roles are not just randomly assigned but are believed to fulfill essential functions. Men’s roles would generally align with instrumental functions (task-oriented), such as providing resources, while women’s roles would align with expressive functions (emotion-oriented), such as providing emotional support and nurturing. Through the differentiation and performance of these gender-specific roles, the structural-functional approach posits that social cohesion is maintained.

Extra: Structural-functional analysis is one of the major theoretical perspectives in sociology that explains how aspects of society are structured and how they function. It was rooted in the work of early sociologists such as Emile Durkheim, who was interested in understanding how societies could maintain integrity and coherence in modernity, where traditional bonds were waning.

In this framework, society is imagined as an organism in which every part has a function that contributes to the survival of the whole. The same way the heart pumps blood throughout the body, or the lungs provide oxygen for the organism’s functions, each part of society is seen as contributing to the overall functioning of the social body.

When applying this analogy to social issues like gender roles, it's worth noting that the structural-functional approach has faced criticism over time. Critics argue that by emphasizing stability and cohesion, this perspective can overlook inequalities, including those associated with gender. It can inadvertently justify the status quo, possibly upholding traditional gender roles and stereotypes which can contribute to gender inequality. It is also critiqued for its lack of ability to deal with social change, as it tends to assume that what currently exists is necessarily functional and desirable.

Moreover, feminists and other contemporary sociologists have challenged the biological determinism in traditional structural-functional understandings of gender, arguing that gender roles are socially constructed and that they can—and often do—change over time and across cultures. They emphasize that "function" is not an objective reality but can be used to justify power relations within a society. Despite its limitations, structural-functional analysis has been foundational in developing sociological thought and understanding how societal institutions work together to produce societal stability.