Waiving parent permission can be an option in some epidemiological and social research with adolescents. However, exemptions have not been uniformly considered or applied. Our aim is to critically assess the different factors that could be taken into account when making decisions about waiving active parental permission in observational research with adolescents.

The objective of this study is to verify the influence of messages Salvadorian youth receive about sexuality, affection, and leisure from family, friends, and the media on the initiation of sexual activity. Cross-sectional study based on a representative sample of 2 615 students (from 13 to 19 years of age) in El Salvador. A random systematic sampling was used to select 30 schools. Sociodemographic aspects, lifestyles, and sources of information on sexuality and love used by the young people were collected. The average age of the young people studied was 15 (SD = 1.8). In all, 638 (24.4%) of the young people stated that they had had sexual relations. The following factors are associated with a greater probability of having had sexual relations: a perception that siblings (OR = 1.8, CI 95%: 1.2-2.7) or friends (OR = 1.7, CI 95%: 1.3-2.2) encourage them to have sex. Protective factors were found to be the supervision of parents (OR = 0.5, CI 95%: 0.4-0.7); messages received from friends that encourage abstinence (OR = 0.7, CI 95%: 0.6-1.0) or from siblings (OR = 0.7, CI 95%: 0.5-0.8); and favorable messages related to marriage received from parents (OR = 0.4, CI 95%: 0.3-0.6). Messages from family and friends are factors that seem to influence the initiation of sexual activity by young people. Sexual health promotion programs in El Salvador should take these factors into account.

In order to achieve a change among teens' sexual behavior, an important step is to improve our knowledge about their opinions concerning relationships, love and sexuality.

Introduction: Sexually Transmitted Infections (STIs) and unplanned pregnancies affect adolescent sexual health and are serious public health concerns. They result from sexual intercourse in adolescence, which is usually associated with multiple partners, unprotected sex, and condom misuse. This behavior is related to socio-ecological factors that influence lifestyles. The YOURLIFE project aims to find out what young people think and feel about relationships, love and sexuality, and to assess the associations between these thoughts and attitudes, adolescents´ social factors, and sexual health. Materials and Equipment: An international school-based study with a cross-sectional and optional subsequent longitudinal design. Three on-line questionnaires designed for adolescents aged 13/14, 15/16 and 17/18 respectively will be used. A matching coding system will allow longitudinal follow-up when adolescents reply to follow-up surveys. Questionnaires will include questions related to socio-demographic data; information/communication technologies; leisure time; parental supervision; influences of parents/friends; information sources; messages perceived; and sexuality-related knowledge, attitudes and opinions. The second and third questionnaire for participants aged 15/16 and 17/18 will also contain variables concerning sexual behavior. Schools will be able to use their results to tailor educational approaches targeting the needs of their students. Multivariate analyses will be performed using the larger international dataset. Expected Impact of the study on Public Health: The YOURLIFE project will collect comprehensive information about the socio-ecological determinants of the sexual risk-taking of schooled adolescents worldwide. Effective preventive programs could be subsequently designed and tailored to the specific determinants of adolescents from different schools and settings and also, when analyzed globally, to public health professionals.