Which theorist argues that gender is a performance and questions the relationship between sex at birth and gender?

Judith Butler is the theorist who argues that gender is a performance and critically examines the connection between biological sex assigned at birth and the socially constructed concept of gender. In her groundbreaking work, particularly in "Gender Trouble," Butler posits that gender is not an inherent, stable identity but rather a set of behaviors, roles, and performances that are enacted and reinforced by societal norms. This perspective challenges traditional binary views of gender and suggests that it is fluid and shaped by cultural contexts, rather than merely a reflection of one's biological sex. Butler’s ideas have significantly influenced gender studies, queer theory, and feminist discourse, making her contributions central to contemporary discussions about the complexities of gender identity.