Human Pappilomavirus (HPV) causes most cases of cervical cancer, as well as penile, anal, and several other cancers. And the CDC recommends the HPV vaccine for all boys and girls ages 11 and 12, teens who didn’t get the vaccine when they were younger, young men up to age 21, and young women up to age 26. Unfortunately, more and more parents are not getting their kids vaccinated, mostly out of completely misplaced fears about the vaccine’s safety and whether it could lead to early sexual activity.

Overall, less than a third of girls eligible for the vaccine actually get it, and of those, only one in three gets all three of the recommended doses. A variety of international studies have shown that HPV vaccines are no more dangerous than any other vaccines (which means they’re pretty darn safe) and that there is no connection between getting the vaccine and promiscuity—for girls or boys.

Now, a recent study from Australia provides even more solid evidence for why the HPV vaccine is important. The vaccine first became available in Australia in 2007. And in the first 4-5 years since it was introduced, the incidence of genital warts among tween and teen girls plummeted by over 90 percent. Until just last year, the vaccine was given only to girls. But even so, cases of genital wards among heterosexual boys and young men dropped by 50-80 percent

You can get more info on the HPV vaccine from the CDC here.
and more on the connection between the vaccine and reduction in genital warts here.

Bottom line, if you have a boy or a girl 11 or older who hasn’t been vaccinated, get it done. It’s safe and it works. What more do you need than that?