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Risk factors

By Mayo Clinic staff

Even between faithful and committed partners, STDs can happen. It's possible to be infected with herpes, for example, and never realize it, then pass the infection to your long-term partner. More often, though, people get sexually transmitted infections from casual or new partners.

Your risk of catching any STD depends on your sex, age and sexual practices, as well as on the sexual practices and lifestyles of your potential partners. The same factors determine which STDs you're most likely to be exposed to.

General risk factors include:

  • Being sexually active. Some activities carry a high risk of transmitting infection. The riskiest activities are anal and vaginal intercourse.
  • Starting sexual activity at an early age. The possibility of catching an STD or becoming pregnant doesn't seem real to many adolescents. If they worry about risk at all, they do so after having sex. Also, the younger you start, the more partners you may have.
  • Having high-risk sex. Vaginal or anal penetration by an infected partner who is not wearing a latex condom transmits some diseases with frightening efficiency. Without a condom, a man who has gonorrhea has a 70 to 80 percent chance of infecting his female partner in a single act of vaginal intercourse. Oral sex is less risky but still too dangerous to chance without a latex condom or dental dam.
  • Currently having an STD. Being infected with one STD makes it much easier for another STD to take hold. If you're infected with herpes, syphilis, gonorrhea or chlamydia and you have unprotected sex with an HIV-positive partner, you're more likely to contract the virus.
  • Having a history of an STD. If you've had one STD, you're at increased risk of catching another one, partly because you and your potential sex partners often belong to social networks made up of people of similar age, location and background. Within these overlapping networks, couples regularly form, split up and find new partners. If one STD is making its way through such a network, there's a good chance that others are, too.
  • Having multiple sex partners, not just concurrently but over time. Every time you break up with one partner and move on to another, even if each relationship is monogamous, your STD risk is increased.
  • Using alcohol or recreational drugs. These habits lower your inhibitions and impair your judgment, so you're more likely to take sexual risks.
  • Injecting drugs. Needle-sharing spreads many dangerous infections, including HIV and hepatitis B. If you acquire HIV by injecting drugs, you can transmit it sexually.
  • Being young. Almost half of the new cases of STDs each year are in people between the ages of 15 and 24 years.
  • Being female. At all ages, women are more likely to have severe STD complications, such as infertility, than are men. In teenage girls and young adult women, the cervix is made up of constantly changing cells. These unstable cells make the cervix more vulnerable to certain sexually transmitted organisms, so vaginal intercourse poses added risks.
  • Being African-American. STDs, particularly gonorrhea and syphilis, are reported in a disproportionate number of African-Americans. This may be partly because African-Americans are more likely to receive care at clinics that report STD statistics, including breakdowns of cases by age, sex and race.
  • Having sex with men. Whether you're male or female, male sex partners are riskier. For women, having vaginal intercourse or performing oral sex on a man without a latex condom is a high-risk activity. Homosexual men are also at increased risk of STDs, as are male and female sex workers and their customers. Some men who have heterosexual relationships also engage in clandestine sex with other men, posing risks to themselves and their partners of both sexes.
  • Meeting people in public places or online for sex. Casual, anonymous sex promotes the spread of STDs across social networks and different demographic groups.
Complications Causes
References
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Feb. 25, 2009

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