Gardasil isn't exactly an anti-cancer vaccine, but it comes close. It protects girls and women against four sexually transmitted strains of the human papillomavirus (HPV), two of which cause about 70 percent of all cervical cancer. It is also extremely controversial, though the nature of the controversy has changed radically since the treatment was invented. This time last year the issue was whether it would be allowed at all, a matter settled in June when the Food and Drug Administration approved it. Today the question is whether the shots should be required. Nearly half the states have been considering measures...