Multiple sex partners

Multiple sex partners (MSP) is the measure and incidence of engaging in sexual activities with two or more people within a specific time period. Sexual activity with MSP can happen simultaneously or serially. MSP includes sexual activity between people of a different gender or the same gender.

The term polyamorous is a behavior and not a measure describing multiple sexual relationships at the same time.

Young people having MSP in the last year is an indicator used by the Centers for Disease Control and Prevention (CDC) in evaluating risky sexual behavior in adolescents and a tool in the monitoring of changes in HIV/AIDS infection rates and deaths worldwide.