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:

1. Should boys get the HPV vaccine?
Men rarely get cancer from HPV, but they do pass the virus to their female partners, and they do get genital warts from HPV as well. In Europe and the U.K., Gardasil is licensed for use in both boys and girls, although so far only Austria's public health program actually recommends vaccinations for both.

The reason it's not generally recommended for boys in the U.S. is because it hasn't been approved for use in boys. General thinking may be, too, that it's more cost-effective, from a public-health standpoint, to vaccinate girls only. And insurance companies won't cover vaccines that aren't recommended. Gardasil retails at around $375 for the three-dose course.

Next Page: What about women over 26? [ pagebreak ]

2. What about women over 26?
Older women and boys are in a similar situation, says Dr. Handsfield. "Women who get beyond their 20s are statistically at lower risk for HPV infection," he says, "so from a public-policy standpoint, it's not a priority." Also, since the research studies that led to Gardasil's approval were limited to the under-26 crowd, it's not FDA-approved for older women.

"But sure, the vaccine almost certainly would work in older women," Dr. Handsfield says. "This'll evolve."

As an older woman, you can pay out-of-pocket and get the vaccine, but it may not help (you may already have those strains of the virus). If you're older than 26 and considering the vaccine, it makes sense to evaluate your sexual history. "Say there's a 28-year-old woman, she's about to be out there dating again, and she's only had three or four partners; she probably is still susceptible," says Dr. Hansdfield. "She clearly needs the vaccine."

3. If I get vaccinated, do I still need to get regular Pap smears?
Yes! Experts agree that the vaccine does not replace the need for regular Pap smears, since it protects only against the strains of the virus that cause 70% of all cervical cancers. You'll still need to protect yourself from the rest with yearly screenings.