A new study by the federal Centers for Disease Control and Prevention (CDC) has found startling figures regarding the prevalence of sexually transmitted diseases (STDs) in teen girls. The study, released at the National STD Prevention Conference in Chicago, looked at 838 US girls aged 14 to 19 and found out that overall, more than a quarter had at least one sexually transmitted disease.

A huge difference in rates was also found between white and Hispanic girls, on one hand, and black girls, on the other hand. While the first group had an infection rate of around 20 percent, almost half of black adolescents had at least one STD. Human papillomavirus, or HPV, affected 18 percent of the girls surveyed, Chlamydia 4 percent, trichomoniasis 2.5 percent and herpes simplex virus 2 percent. Overall, 15 percent had more than one disease.

"High S.T.D. infection rates among young women, particularly young African-American women, are clear signs that we must continue developing ways to reach those most at risk," said Dr. John M. Douglas Jr. to NY Times. Dr. Douglas directs the CDC division for STD prevention.

The figures are better understood when taking additional data into account: about 50 percent acknowledged they are sexually active, and 40 percent of them were infected by at least one sexually transmitted disease. Around 3.2 million female teens in the United States are infected with STDs. They cause infertility, cervical cancer, genital warts, pelvic inflammatory disease and other problems.

The data analyzed was from a 2003-2004 survey, and in the present rates may be even higher. "Current public health policies are clearly failing to reduce the spread of STDs among young women," stated Wendy Wright, President of Concerned Women for America in a statement.

"Pushing kids to be sexually active, withholding medical screenings to deny parents information about their teens, and encouraging young women to skip screenings for STDs are irresponsible policies that have put teens' health at risk," he added.