Who was the first sociologist to focus on gender role differences?

The correct choice reflects the contributions of a prominent sociologist who significantly advanced the understanding of gender roles within the framework of sociology. Parsons is often recognized for his work in developing the concept of gender roles as part of his broader theories on social systems and the stability of society. He posited that men and women have distinct roles that contribute to the functioning of the family and society at large.

Parsons' analysis centered on the idea that traditional gender roles, wherein men take on instrumental roles and women take on expressive roles, were essential for maintaining social order. This differentiation suggested that reinforcing these distinct roles would promote harmony within social structures.

In contrast, other sociologists, like Durkheim, focused on broader aspects of social cohesion and integration, while Marx emphasized conflict and economic structures. Weber's work primarily revolved around social action, authority, and bureaucracy, rather than specifically addressing gender role distinctions. Thus, Parsons’ focus on gender roles clearly defines him as the first sociologist to specifically examine and theorize about these differences in a systematic way.