Duration and intensity. Interventions varied widely in length and intensity. The shortest program was a single e-mail and the longest consisted of 24 ? 45-minute sessions administered over 2 years . Some programs were administered in a way that standardized intervention exposure among participants , whereas in other studies, intervention activities were self-directed . Content. The content of most interventions covered basic information such as HIV/STI transmission dynamics, testing for HIV/
STIs and pregnancy, reproduction and pregnancy, and risk reduction strategies, including contraceptive use, condom use, and avoidance of drugs and alcohol. Four programs addressed participants’ skills in areas such as condom use, contraceptive
use, and refusing sex. Some interventions took a comprehensive approach to sexual health and included content on subjects like intimate partner violence , personality traits associated with general risk taking , healthy friendships , and healthy dating relationships .