Why do we have an STD epidemic?

In the early 1960’s there were two common STDs in the United States: syphilis and gonorrhea.  Today there are over 25.  That’s a big change.  Why do we have so many STDs today?

The primary reason is that people today have, on average, more sexual partners than they did in the past.1 The more sexual partners a person has, the greater their chance of catching and spreading STDs.  Check out the sexual exposure chart below.

[Copyright Heritage House ’76] 2

Former U.S. Surgeon General, C. Everett Koop, said, “When you have sex with someone, you are having sex with everyone they have had sex with for the last ten years, and everyone they and their partners have had sex with for the last ten years.”


  1. Michael RT, Gagnon JH, Laumann EO, Kolata G.  Sex in America: A Definitive Study.  Boston, MA: Little Brown and  Company; 1994.
  2. This chart represents an average risk of exposure, based on the formula: F(n) = 2n -1 where n is the number of partners.