Some commenters thought the statistics for teenage STDs seemed inflated but others find them believable:

Elizabeth Alderman, adolescent specialist at the Children’s Hospital at Montefiore Medical Center in New York was astounded by a federal report this week showing that two out of five teenage girls who have had sex have experienced at least one sexually transmitted infection.

Lorena Granados, a junior at W.T. Woodson High School in Fairfax County was not the least bit surprised.
“A lot of girls fall in love, and it doesn’t seem they care about protection,” she said yesterday. “It’s ‘What am I going to enjoy right now?’ Or they’ll say, ‘I know he hasn’t been with anybody. . . . He’s clean.’ Or, ‘He’ll stop before we go too far.’ ”
That same attitude shows up in doctors’ offices, Alderman said yesterday.
[…]
“What we see on the ground on the front lines really confirms the study,” said Shannon Hader, senior deputy director of the D.C. Health Department’s HIV/AIDS Administration.
Hader and other public health officials said a large number of young people have unprotected sex, many with multiple partners. In a 2007 study by the D.C. public school system, 60 percent of high schoolers and 30 percent of middle schoolers reported having had intercourse. Twenty percent of the high school students said they had had sex with four or more people, and 12 percent of the middle schoolers said they had had three or more partners.
[…]
Love said many clients initially visit the clinic for HIV testing only to learn that they have other, more common STDs. Many aren’t aware that diseases such as gonorrhea and chlamydia often don’t exhibit obvious symptoms, she said.

(via)