How do teachers of science in Secondary Education think about the notion of development of their students?

In this article we provide some theoretical and methodological guidelines to understand the conceptions of the development in students, underlying the thinking of science teachers of secondary education, and considering a group of 99 teachers, who were given a Questionnaire of Development, from which only 3 were considered. The way in which the referential dimensions operate was identified; an effect of "referential adjustment" was found, as well as inconsistencies and imbalances in the theoretical referential dimensions of their conceptions. The most significant results coincide with research that identifies the variability, mixture and effect of hybridization of conceptions, which go from the naive and traditionalist to the more sophisticated, making teachers' speeches and actions more complex.