Funded by the International Planned Parenthood Federation, the study on the effects of a transformative gender education on teenagers in Portugal is the first of three stages of a four-year study funded by the European Union's programme Citizens, Equality, Rights and Values. The first stage consists on the designing of the methodology that will be applied in the base study, as well as in its subsequent phases. This study aims to assess the knowledge and attitudes on gender equality and gender violence of teenagers whose school curricular inclueded sex education. CIEG's researchers Sofia Neves, Joana Topa and Estefênia Silva were part of the research team.