In the context of the European research project Biohead-Citizen, 5,706 in-service and pre-service teachers from 14 countries (most in Europe, but also in Africa and Middle East) filled in a questionnaire containing 16 questions mainly related to the existence and to the origins of differences between men and women. We analyse the teachers' answers on biological gender differences, as possible interactions between their scientific knowledge (K) and values (V). Nine questions were focused on possible KV interactions, dealing with biological and / or social differences between men and women. Five questions were related only to scientific knowledge and two questions only to values. In each country we applied the questionnaire to six different samples : pre-service and in-service primary schools teachers , and biology and national language upper schools teachers . The answers were submitted to multivariate analyses. The results confirm that biology teachers have more scientific knowledge on this issue than their colleagues. Nevertheless, the answers to questions related to sexist or hereditarianist values show very significant differences among countries, the less economically developed countries being more sexist than the other ones. There is a significant gender effect for the sexist variables. The ratio men / women being different from one country to another, and inside the six samples in each country, we suppressed these two effects to show that the gender effect is still significant independently to these variables. Female teachers are significantly less sexist than their male colleagues.