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Risk Factors for Sexually Transmitted Infections (STIs)


Risk factors for sexually transmitted infections (STIs) include:

  • Having unprotected sex. People who do not use condoms have a higher risk of getting an STI.
  • Being sexually active at an early age. Sexual activity before age 18 may increase the risk of getting an STI, because teens may have more sex partners or they may be less likely to use condoms to reduce their risk. Girls younger than 18 get STIs 2 to 3 times more often than those older than 18. The cells of the transformation zone of the cervix are more susceptible to infection in teen girls.
  • Having more than one sex partner.
  • Having a high-risk sex partner (one who has other sex partners).
  • Participating in prostitution.
  • Using birth control pills without using condoms.


By Healthwise Staff
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Specialist Medical Reviewer Devika Singh, MD, MPH - Infectious Disease
Last Revised December 11, 2012

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