In its 2011 Youth Risk Behavior Surveillance report released in June, the CDC found that teen condom use remained near the 60 percent range (60.2). This continues the trend that saw usage rise from 46.2 to 63.0 percent from 1991-2003 and then plateau, with only statistically negligible changes since.

Despite this, the CDC estimates the young adult population (ages 15-24) account for almost half of the estimated 19 million new STD infections every year, while comprising only 25 percent of the sexually active population.

"Rates of oral contraceptive use among females in this age range have increased, which helps explain the lower birth rate," said Dr. David Hager, Ob/GYN and a member of Focus on the Family's Physicians Resource Council.

Hager, author of "Women at Risk: The Real Truth About Sexually Transmitted Diseases," also attributes part of the decrease to the 40 percent of teen pregnancies that end in elective abortion.