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