Our paper analyses the genetics and gene technology contents of German (Bavarian) and Portuguese biology textbooks, as fields common in science-technology-society-environment (STSE) issues. Our aim was to determine the extent to which textbooks from both countries contribute to students' understanding of the STSE issues and therefore to students' scientific literacy (SL), as well as to detect indicators of the Decontextualized and Socially Neutral View of Science and Technology (DSNVST), as a barrier for achieving that goal. We qualitatively and quantitatively inspected eight textbooks according to previously proposed criteria and sub-criteria: four Portuguese textbooks (two each for the 9th and 12th grade) and four German textbooks (two each for the 9th and the 11th grade). Based on compliance with our set of criteria and sub-criteria, we identified 2390 STSE statements attempting to approach STSE issues, but we also found important lacks in all textbooks and detected DSNVST indicators. Finally, we discuss possible linkages between these indicators and the socio-cultural background underlying textbooks, in terms of both educational policies determining curricula, and prevailing public attitudes towards science. Some similarities within each nationality, as well as some divergences between them endorse our hypothesis that the socio-cultural context from which textbooks emerged determined the choice of STSE content, the discussions employed, and the conception of science and technology displayed by the textbooks.