Blake, C. K.; Ewa, O. S.; Eckles, E. B.

Lesbian, gay, bisexual, transgender, queer, intersex, and asexual (LGBTQIA+) students continue to face violence, exclusion, and barriers at school, including in STEM education. A key underexamined factor in diversity, equity, and inclusion (DEI) efforts is the content of the life science curriculum, which is uniquely positioned to reinforce or refute bioessentialist, binary, and heteronormative biases. Outdated science curricula not only conflict with current scientific evidence but can also perpetuate beliefs that contribute to sexism and LGBTQIA+ marginalization. To address this, we designed four gender and sexual diversity (GSD)-inclusive biology activities, aligned with NGSS standards, and informed by inclusive curriculum frameworks. Using a mixed-methods approach, we studied 127 high school students who participated in two or more inclusive biology activities. Surveys conducted before and after implementation showed significant reductions in essential, binary beliefs about sex and gender, and increases in affirming attitudes toward sex and gender diversity. Interviews conducted after implementation further revealed differences between LGBTQIA+ and straight students' conceptualizations of biological sex. Our findings demonstrate that even brief curriculum interventions can shift student attitudes, although we hope future studies will explore the impact of sustained interventions. Updating life science instruction is essential for educational equity and scientific accuracy.