Objective: To compare the knowledge on human sexuality showing ninth year students and teachers of different subjects from a public school of the Canton Central de Alajuela, Costa Rica. Method: the collection of information is made by means of a questionnaire validated prior to ninth grade and young teachers from a public school. We selected a simple random sample of 33 students from a total of 181 active until November 2011. A total of 12 teachers responsible for teaching different subjects (science, social studies and civics, and castilian literature, foreign language, physical education, arts and orientation) ninth level up the sample of teachers. The quantitative data analysis was performed using SPSS 20.0 and Excel. Results: The comparison between students and teachers on four themes assessed (emotional ties, gender roles, human reproduction and sexual response and eroticism) indicates that none of the groups failed to reach a score of 7.0 (scale of 1-10). 6.0 A note is only surpassed by teachers on issues related to "sex roles", while students barely this note in content "emotional ties", interestingly respect in which teachers outperform in terms of average final grade. Conclusions: The poor formation showing the students directly associated to such limited knowledge of teachers. In their academic preparation for general education in Costa Rica, and students do not receive specific training on the subject. It requires real coordination between the Ministry of Education and the universities, in terms of training essential that irreplaceable and should receive urgent and future teachers.

Keywords: knowledge of sexuality, ninth youth, teachers, basic general education