NCPA - National Center for Policy Analysis


June 10, 2008

On March 11, the Centers for Disease Control and Prevention (CDC) announced that one in four teenage girls has a sexually transmitted disease.  This eye-popping statistic made headline news everywhere. 

Neil Munro of the National Journal investigates the study that led to this statistic and found several serious shortcomings that undermine its validity and its usefulness:

  • For instance, the CDC's data referred to "infections"; most biological infections never turn into disease, and therefore "disease" has been improperly conflated with "infection."
  • They interviewed a broad range of females ranging from 14 (only 13 percent of whom have ever had sexual intercourse) to women as old as 19 (70 percent of whom have had sex).

The CDC declined to describe the infection rates in each of the two-year age grouping, even those where they did possess the data.  Other shortcomings:

  • The most common infection found among the girls was from HPV, which can disappear on its own. 
  • The one-in-four number was culled from a complex database that included only several hundred women under age 20; this finding carries a large margin of error, since a total of 838 girls were interviewed in the study. 
  • The CDC's tests also show that none of the 18-and 19-year old women in the study were infected with HIV or syphilis, the two most-feared diseases.

While other CDC research shows the infection rates for most serious sexual diseases, including syphilis, gonorrhea and chrancroid are sharply below 1990 levels, the CDC failed to mention this in the press release.

Sexual activity among females has declined 20 percent from 1998 to 2002; sexual activity among males has declined 40 percent.

Source: Neil Munro, "Birth of a Number," National Journal, May 31, 2008.


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