We discuss several methods of prevention—steps that can be taken before, during, or shortly after sexual contact to reduce the likelihood of contracting an STI. Many of these methods are effective against the transmission of a variety of infections. Several are appli­cable to oral-genital and anal-genital contacts in addition to genital-genital interaction.

None of the methods is 100% effective, but each method acts to significantly reduce the chances of infection. Furthermore—and this cannot be overemphasized—the use of pre­ventive measures may help to curtail the booming spread of STIs. Because many infected people have sexual contact with one or more partners before realizing that they have an infection and seeking treatment, improved prevention rather than better treatment seems to hold the key to reducing these unpleasant effects of sexual expression.