HPV associated genital dysplasia is a complication following hematopoietic allogeneic stem cell transplantation (HSCT). In a recent study from this institution, one third of female transplant recipients had HPV related genital tract dysplasia. The quadrivalent human papillomavirus virus (HPV) (types 6, 11, 16, 18) vaccine (Gardasil ) is now approved for use in females aged 9-26 for the prevention of cervical cancer and, more recently, vulvar and vaginal cancer. In this study, Gardasil will be used in females age 18 years to 50 at least 90 days post stem cell transplant in two study cohorts to determine its safety and immunogenicity in this population, as a first step to reduce post-transplant HPV-related co-morbidity, genital dysplasia and malignancy. The two study cohorts will both be post transplant; one off of immunosuppression (n=24), and one on immunosuppression (n=24). Gardasil will be administered using the FDA approved regimen of 3 separate 0.5ml intramuscular injections at 0, 2, and 6 months. The primary objectives of this study are to determine the safety and immunogenicity of Gardasil in female allogeneic HSCT recipients. A cohort of healthy subjects will also be vaccinated (n=24) and will serve as a control. Immunogenicity studies characterizing the CD4 and CD8 T- cell response, change in antibody titer and cytokine response from baseline to months seven and twelve will be compared in the three cohorts. Additionally, genital exams will be performed to monitor for HPV. Secondary endpoints will characterize sexual function post-transplant and vulvar/vaginal graft-versus-host disease (GVHD). When available, healthy female stem cell donors corresponding to enrolled vaccine recipients will be enrolled (n=10) as part of the healthy cohort and vaccinated to determine whether there are differences in HPV vaccine immunogenicity in a subset of donors and their respective allogeneic, HSCT female recipients.