This study will last 12 months and participants will visit the clinic 15 times. Participants will receive three injections of the VRC-HIVDNA016-00-VP vaccine at Months 0, 1, and 2 followed by an injection of VRC-HIVADV014-00-VP at Month 6. All injections will be given in the upper arm. At study visits participants will have a physical, medical history taken, blood collection, and risk reduction counseling. At some visits, rectal biopsies (via anoscopy or, optionally, by flexible sigmoidoscopy), saliva, semen, cervical and/or vaginal fluid samples will also be collected. Pregnancy testing for women will be done prior to each vaccination and study procedure.