The Centers for Disease Control and Prevention (CDC) in the United States has revealed that a quarter of teen girls have a sex-related disease.
The CDC says the rate is highest among blacks and more than one in four U.S. teen girls is infected with at least one sexually transmitted disease.
The CDC says 48 percent of black teen-age girls are infected, compared to 20 percent of whites and 20 percent of Mexican American girls.
According to the CDC this equates to 3.2 million U.S. girls ages 14 and 19; about 26 percent of that age group have a sexually transmitted infection such as the human papillomavirus (HPV), chlamydia, genital herpes or trichomoniasis.
Dr. Sara Forhan, who led the study for the CDC says the numbers are alarming and mean that many young women are at risk for the serious health effects of untreated STDs, including infertility and cervical cancer.
Dr. John Douglas, director of the CDC's Division of STD Prevention, blames a complex mix of factors for the higher rates among black girls, including the overall higher presence of sexually transmitted diseases, or STDs, in the broader black community.
More alarming is the fact that the figure may well be higher because the study did not look at syphilis, gonorrhea or HIV infection as these are generally are uncommon in teenage girls.
The CDC says the report is the first to gauge combined rates of common STDs in female adolescents.
Among girls who had an STD, 15 percent had more than one and about half reported ever having had sex, and among those girls, 40 percent had at least one STD; of girls who had just one lifetime sexual partner, 20 percent had at least one STD.
The most common infection HPV, which can cause genital warts and cervical cancer, was seen in 18 percent of the girls.
The CDC says this indicates teenage girls, even those with few lifetime sexual partners, are at high risk for HPV infection.
The CDC is urging girls and women ages 11 to 26 who have not been vaccinated against HPV or who have not completed the full series of shots be fully vaccinated against the virus.
The second most common infection was chlamydia which was seen in 4 percent of the girls which can damage a woman's reproductive organs and left untreated can spread into the uterus or fallopian tubes and cause pelvic inflammatory disease; it also raises the risk for infertility.
The CDC is calling for yearly chlamydia screening for sexually active women under age of 25.
Trichomoniasis, caused by a single-celled parasite, was seen in about 3 percent of the girls, it causes vaginal itching and discharge and about 2 percent of girls were infected with herpes simplex virus type 2, which causes most cases of genital herpes.
Experts say some doctors are reluctant to discuss screening with teenage patients because of confidentiality concerns as parents must be told of the results.