Inheritance of traits (heredity) is a conceptually demanding topic for Grade 9 junior high school students. It requires learners to coordinate abstract entities (genes/alleles), symbolic representations (Punnett squares, pedigrees), and probabilistic reasoning—conditions that often produce misconceptions and low confidence. At the same time, junior high science curricula increasingly emphasize higher-order outcomes such as critical thinking and sustained learning interest, not only factual recall. The OIDDE learning model (Orientation–Identify–Discussion–Decision–Engage in behavior) was developed as a staged inquiry model to guide learners through dilemma-based reasoning and responsible action. Evidence from higher education and secondary contexts indicates that OIDDE can foster higher-order thinking (including critical thinking), ethical decision making, and learning engagement when implemented with appropriate scaffolding (Hudha et al., 2016; Husamah et al., 2018; Hudha et al., 2024). This article provides a framework synthesis (≤2024) to argue for the urgency of applying OIDDE to the inheritance topic in junior high school. We integrate three research strands: (1) the structure and documented impacts of OIDDE; (2) evidence on conceptual difficulties and misconceptions in genetics learning; and (3) motivation research on learning interest and autonomy-supportive instruction. Results include an explanatory framework linking OIDDE stages to motivational mechanisms and cognitive mechanisms, and we translate the framework into a lesson flow and assessment checkpoints for Grade 9 heredity. We also provide an evidence map, a stage-by-stage activity template, and rubrics for critical thinking and interest measurement.