Competitive sport is often a gender-segregated activity underpinned by binary thinking that associates sporting talent with masculinity. In response to political, internal and grassroots activism, the English Football Association conducted a series of pilots to ascertain whether they should raise the age limit for competitive mixed football from Under-11 to Under-14. This paper presents an analysis of these trials using the concepts of accountability, doing and undoing gender to explore participants’ support for policy change, and the ways that normative notions of gender were negotiated, reproduced and disrupted during the trials. Typical rationale for segregating sports which constitute gender accountability frameworks such as physical differences between boys and girls, perceived differences in ability, and concerns about risk of injury for girls were undone as girls demonstrated they could make the team, enjoy the experience and develop their skills in a safe environment. Key arguments in favour of mixed football included the benefit to female players, the importance of friendships between boys and girls, and the similarities in boys’ and girls’ footballing skills. Support for mixed football and policy change reflected participants’ expectations that girls should be assessed on their capacity to play football and ‘fit in’ rather than expectations of gender difference. This article contributes to the limited research on mixed competitive youth sport and provides unique insights into gender-based policy change.