Although they are most often caused by viruses that differ in less than 17 percent of their genome, and can even be caused by the same virus, genital herpes and oral herpes are perceived very differently by the general public. Genital herpes, usually caused by HSV-2, is a scourge to frighten children, while oral herpes, usually caused by HSV-1, is just a fact of life.
Just about everyone knows someone plagued by cold sores, but very few people realize that they are caused by the herpes virus HSV-1. Oral herpes, i.e. cold sores, is an extremely common infection. There are estimates that approximately one in every two Americans is infected with HSV-1, and the numbers could easily be substantially higher since so many cases are asymptomatic.
Still, HSV-1 and HSV-2 are barely different at all. They are so similar, in fact, that, although HSV-1 preferentially infects the mouth area and HSV-2 preferentially infects the genitals, they are quite capable of jumping from one site to the other during oral sex. Several studies have found that, in recent years, at least half of all first outbreaks of genital herpes were actually caused by HSV-1 not HSV-2.
So why is there such a strong social stigma associated with genital herpes, but not with oral herpes? Because Americans still associate shame with sex or feel dirty about their sexual activities. The herpes viruses HSV-1 and HSV-2, however, show quite clearly how arbitrary, and silly, such judgments are.
After all, why should you be judged for having one virus instead of another when the two do almost exactly the same thing?
Gupta R, Warren T, Wald A. (2007) "Genital herpes." Lancet, 22;370(9605):2127-37
Xu, F. et al. (2006) "Trends in Herpes Simplex Virus Type 1 and Type 2 Seroprevalence in the United States" JAMA, 296:964-973