CHICAGO -- More than 3 million teenage girls have at least one sexually transmitted disease, and 15% of those have multiple infections, according to the first large study of STDs in this population.

Overall, 26% of 14- to 19-year-olds were infected with at least one STD, according to the population-based study sponsored by the Centers for Disease Control and Prevention. Black teens had the highest prevalence of disease, with 48% testing positive for at least one of the four most common sexual infections, compared with 20% of white teens, investigators reported in a press briefing during a CDC-sponsored conference on STD prevention.

"For any other disease, we would be ...