Four out of every 10 new HIV infections in the United States occur in people younger than 30, according to Centers for Disease Control and Prevention (CDC) research reported by The Huffington Post. Using a long-standing survey of high school students' health, the CDC tracked how teen sexual behavior has changed over 20 years. The results were mixed. About 60 percent of sexually active high school students say they used condoms the last time they had sex, researchers said when presenting its findings at the XIX International AIDS Conference. That's a slight drop from a high point of 63 percent reached in 2003, but it also marks an increase from the 46 percent who were using condoms in 1991. Today, black students are most likely to heed the safe-sex message, yet their condom use dropped from a high of 70 percent in 1999 to 65 percent last year, the study found. The proportion of high school students who've had sex is 47 percent today—down a bit from 54 percent in 1991—and they typically start at age 16, the CDC reported. Black teens showed a bigger decrease, with 60 percent sexually active today compared with 82 percent two decades ago.

To read the Huffington Post article, click here.