What You Need to Know About the HPV Vaccine, and Why It's Controversial

Almost everyone carries the human papillomavirus (HPV), and it's usually pretty harmless. But a few strains are the main cause of cervical cancer. Gardasil, the HPV vaccine approved by the FDA in 2006, guards against two of these strains, plus two other strains that are responsible for most genital warts.

Since most adults have already been exposed to HPV, the vaccine is recommended for girls who haven't become sexually active yet. (The federal Centers for Disease Control and Prevention recommends vaccination at age 11 or 12, but Gardasil is approved for girls as young as 9.)

So far, so good. But the introduction of this new vaccine has stirred up a small fuss.

The controversy
Perhaps the main fear of the vaccine's opponents is that it might encourage adolescent promiscuity.

H. Hunter Handsfield, MD, a clinical professor of medicine at the University of Washington and a nationally recognized STD expert, believes most parents are all for it, however. "It can prevent cancer?" he says, parroting the most common parental concern. "Well, duh, give my kid the shot."

Still, questions come up all the time because the vaccine is so new. Here are a couple of the most common: