Third-party informed consent in research with adolescents: the good, the bad and the ugly.

Third-party informed consent for child and adolescent participation in research is a legal requirement that has been questioned by authors who argue that children over 10 are fully able to make decisions regarding this matter. The extent to which this requirement encumbers survey researches in this age range has not been fully reported. In order to understand the reasons for the inconsistent use of condoms among adolescent students in Rio de Janeiro, we designed a survey based on an anonymous self-reported questionnaire.