Understanding Silence in Science Education: Emotional, Personal and Motivational Barriers Facing Comprehensive Sexuality Education—A Systematic Review

Classroom silence remains a persistent pattern in science-based sexuality education, despite the recognised importance of including sexual and reproductive health in formal curricula. Though scholars have identified various barriers to comprehensive sexuality education, little attention has been given to how these barriers interact over time to shape teachers’ instructional responses. This qualitative systematic review was guided by PRISMA 2020 and analysed 30 peer-reviewed studies published between 2015 and 2025 that were identified by searching Scopus, ERIC and SciELO. Findings were synthesised thematically. Quality appraisal guided interpretation but did not exclude studies. The review identifies three recurring patterns relating to barriers, namely emotional discomfort, limited perceived capacity, and institutional constraints, which frequently co-occur across contexts. These barriers shape classroom engagement by narrowing discussion, redirecting sensitive questions and confining content to biological explanations. Emotional discomfort often emerges early, though its influence is mediated by teachers’ self-efficacy and by institutional conditions that signal professional legitimacy and risk. Over time, these interacting pressures lead to repeated instructional adjustments that stabilise into instructional silence as a professional response. This study proposes a pathway framework for explaining how emotional, personal and structural factors interact dynamically in shaping classroom practice. The findings highlight the limits of isolated interventions and point to the need for coordinated support, including teacher professional development, clearer curriculum guidance and stronger institutional support. This framework provides a foundation for designing more effective teacher support systems, which could enable more confident and sustained engagement with sensitive topics in science classrooms.