Taking a thorough sexual history is the basis of identifying high-risk sexual behavior, screening, counseling, and treatment for sexually transmitted infections (STIs). Older men and women should continue to be screened throughout their lifetime for STIs; there is no cutoff on age for the transmission of STIs. All persons who seek evaluation and treatment for STIs should be screened for HIV. Screening should be routine, regardless of whether the patient reports any specific behavioral risk for HIV. The Centers for Disease Control and Prevention (CDC) recommends that persons 13 to 64 years of age be screened for HIV in all healthcare settings. Persons should be notified that testing will be performed, but retain the option to decline or defer testing. Guidelines and recommendations for HIV/AIDS for clinicians are available at the CDC website located at  www.cdc.gov/hiv/guidelines/index.html. For more discussion on sexual health and treatment guidelines for STIs and HIV see section “Sexual Health Issues in the Aging Population” of Chapter 17; full CDC STI guidelines in Chapter 18; and section “HIV” of Chapter 20.