Imagine a vaccine that would protect women from a serious gynecological cancer. Wouldn't that be great? Well, both Merck and GlaxoSmithKline recently announced that they have conducted successful trials of vaccines that protect against the human papilloma virus. HPV is not only an incredibly widespread sexually transmitted infection but is responsible for at least 70 percent of cases of cervical cancer, which is diagnosed in 10,000 American women a year and kills 4,000. Wonderful, you are probably thinking, all we need to do is vaccinate girls (and boys too for good measure) before they become sexually active, around puberty, and...