Background: The need to meet the demands of education in the 21st century has seen Namibia move, after democracy in 1990, from a segregationist educational system to an inclusive one in a bid to develop students' capacities to think critically, particularly in science. Research indicates that cultural taboos can impact on how science knowledge is transmitted to and acquired by students. Objectives: The objective of this study is to investigate whether and how cultural taboos impact on the teaching of science in a Grade 4 class in Namibia. Method: Using a single case study design, we investigate the impact of cultural taboos on students' acquisition of concepts relating to sexual reproduction and excretion, focusing on the extent to which cultural taboos influence talk as a mediating tool. Results: Findings indicate that cultural taboos silence students and impede the teacher's ability to unpack sensitive concepts in science, potentially creating misunderstandings. Conclusion: Cultural taboos impact how effectively sensitive science concepts are mediated in this context. Contribution: This article adds to the knowledge of cultural taboos in science teaching but also develops a view of science teaching in a disadvantaged rural area where children are being taught in English, not their mother tongue. The use of cultural historical theory, we feel, also adds a fairly tale lens to the understanding of how scientific concepts must be linked to everyday concepts for student acquisition.