Dr. Donald Brown inoculated Kelly Kent with the HPV vaccine in his Chicago office in the summer of 2006 — not long after the first version of the vaccine reached the market. Charles Rex Arbogast/AP hide caption

itoggle caption Charles Rex Arbogast/AP

First-year medical student Michelle Gentile assists her classmate Abbie Harts as she performs a pelvic exam on a volunteer at Northwestern University. Joshua Lott/Reuters /Landov hide caption

itoggle caption Joshua Lott/Reuters /Landov

Two cervical cancer cells divide in this image from a scanning electron microscope. Steve Gschmeissner/Getty Images/Science Photo Libra hide caption

itoggle caption Steve Gschmeissner/Getty Images/Science Photo Libra

The human papilloma virus causes most cervical cancers. That's why HPV testing is now recommended for women ages 30 to 65. Science Photo Library hide caption

itoggle caption Science Photo Library