In 2001, the Greek Government introduced sex and gender relationships education as a thematic unit for interdisciplinary Health Education activities. However, the diffusion of such programmes remains extremely limited. The present paper discusses how sex and relationships issues are presented in contemporary Greek primary school textbooks since textbooks play a central role in teaching and learning processes. It has been found that textbook references on a particular topic encourage teachers to select this topic for developing and implementing Health Education projects. In this paper the recent educational reform is presented, as well as the general guidelines for the development of the National Curriculum and Health Education Subject Curriculum, the contents of which determined the guidelines for the development of the new primary textbooks. Within this framework, the article discusses how sex education issues are being represented in primary "Environmental Studies"/"Science" and "Mother Tongue"/"Literature" textbooks. Findings support the claim that such representation is limited and single-dimensional, placing sex education at the margins of educational interventions in Greece at the moment. The marginalization of sex education, as it is argued, can be regarded as the effect of conflicting societal values. (Contains 2 tables, 1 figure, and 7 notes.)