The other reason it's so hard to know just who is most at risk for STDs these days is that the infections are so widespreadand often so invisible. "Many of the people who are transmitting sexually transmitted disease are not symptomatic, so it's often the person who has normal looking genitals that poses the risk," says Myron Cohen, MD, director of the Institute for Global Health and Infectious Diseases at the University of North Carolina School of Medicine.
"Most people [with herpes] don't have herpes lesions," echoes Anne Foster-Rosales, MD, chief medical officer for Planned Parenthood Golden Gate. "Same thing with HPV: It's an invisible virus."
Chlamydia is another very common STD with a low profilethis one with devastating effects on women. And of course there's HIV, an incurable STD that is fatal without treatment.
If you are in a monogamous partnership and you have both tested negative for HIV and other STDs, you're at very low risk. But your partner may not be as monogamous as you think, and there are some diseases your partner may not realize he or she is carrying.
The bottom line: If you practice safer sex, your risk goes down.