STDs/STIs have enormous effects on the health of individuals and society. Consequently, STIs are an active focus of NICHD’s research. While many effective, commonly available interventions can reduce the incidence of STIs, these interventions are not always implemented, in part because of complicating social factors. As a result, STIs are often difficult to prevent, diagnose, and treat, and this situation has a serious impact on public health. NICHD’s portfolio covers a variety of topics in STI research with a focus on understanding epidemiology and improving screening, education, and preventative health interventions.