Despite authority’s centrality to the medical profession, providers routinely forgo their medical authority during clinical encounters. Research focuses on patients challenging medical authority but indicates these confrontations are uncommon and providers seldom relinquish their authority in response. Using rare data of 75 audio recordings of adolescent vaccine discussions during clinical encounters and interviews with and observations of medical staff, I examine how staff leverage or abandon their medical authority to convince parents to vaccinate. I find medical professionals use less authority when at risk of stigmatizing patients: Medical professionals are less authoritative when recommending human papillomavirus (HPV) vaccination versus other adolescent vaccines, particularly when addressing the need to vaccinate before sexual onset due to concerns of labeling the child as sexually active. Medical staff defer to parents in ways that potentially discourage HPV vaccine uptake: They encourage HPV vaccination less than other vaccines and infrequently challenge parents’ sex-related reasons for vaccine refusal.