Globally, many people with a sexually transmissible infection (STI) acquired it vertically during pregnancy or the puerperium, others by blood products or injecting drug use but, nevertheless, may transmit the infection sexually. The sexual history should be appropriate, rather than exhaustive, but structured. It is best undertaken where the conditions are most likely to support the patient in being truthful in her/his responses. The sexually transmitted sliding scale is a model devised for this chapter, to aid the approach to clinical scenarios that may be due to STI. The reason for highlighting the model is that many conditions, including pelvic inflammatory disease (PID), would have a score somewhere in the middle and awareness of this informs the approach to the management of such conditions. The causes for STIs discussed in the chapter include genital ulcer disease, vaginal symptoms and balanitis, lumps and rashes, and glandular fever-like illness.