It's a vaccine. You can get it at 9, and still be prceeottd at 30, 40, etc. They last a lifetime. They suggest it at 9, because it seems from the research that the earlier you get it, the better it works. It's just a vaccine against 4 strains of human papillomavirus, some of which can cause cervical cancer, others cause warts, etc. I think it's kind of cool, one less health problem for these girls to worry about when they grow up.