Our study focused on two topics, Sexually Transmitted Infections (STIs) and their control using condoms. For this, we analysed and compared 42 school textbooks from 16 countries on the general topic "Human Reproduction and Sex Education" using a specific grid designed by the BIOHEAD-Citizen project. Acquired Immune Deficiency Syndrome (AIDS) was a common topic in all the textbooks that were analyzed, although it appeared in quite different chapters, such as, Human Procreation (the control of reproduction, the hygiene of reproduction, or in chapters devoted to STIs and AIDS), Immunology (with AIDS as an example of immune deficiency), and Personal Protection. Some textbooks provided information about other STIs in addition to AIDS. There appeared important differences among countries concerning both the number of images in the textbooks and the number of STIs that were discussed in the textbooks. There were also differences among various textbooks addressing the same educational level that came from different publishers in terms of the way that STIs were presented. More than half of the analyzed textbooks did not link the presentation of STIs with their prevention via the use of condoms, and only a few textbooks illustrated an unrolled male condom on the penis. Our results also indicated that (i) for most of the analyzed biology textbooks there was a preference for the biomedical model of health education that provided sufficient scientific knowledge, (ii) only in Finland, there was an attempt for promoting competencies relating to a healthy sexual behaviour, and (iii) the textbooks from Morocco and Tunisia illustrated how traditional values could be promoted in parallel with biomedical knowledge by using injunctive moral content. Interactions between scientific knowledge (K), values (V), and social practices (P) had been found and seemed to determine what was present (and how)in school textbooks. (Contains 6 tables and 13 figures.)