The human papillomavirus (HPV) vaccine provides physicians with an opportunity to have conversations with girls about sex and sex-related topics. Current research suggests that these conversations are not happening. This study was designed to assess whether physicians would use the HPV vaccination as an opening to communicate with nine-year-old to 15-year-old female patients about sex using the Theory of Planned Behavior as a framework. The study also assessed what sexual health topics physicians were willing to discuss when they vaccinated patients and at what ages they would be willing to discuss each topic. Differences in communication were also examined between older and younger physicians and female and male physicians. A random sample (n = 207) of all family practice and pediatric physicians in a rural, Midwest state in the USA were mailed a survey about the HPV vaccine and their intentions to talk about sex-related topics. Specifically, the survey questions assessed the theoretical constructs: attitudes, subjective norms, and perceived behaviour control. The results point to physicians' intentions to talk about sex when they vaccinate. Most physicians intended to talk about sexually transmitted infections when they vaccinate against HPV (90.3%). A multivariate linear regression reveals that physicians' intentions to talk about sex are influenced by attitudes ([beta] = 0.18, p less than 0.05), subjective norms ([beta] = 0.53, p less than 0.001), and perceived behavioural control ([beta] = 0.15, p less than 0.05). Physicians intended to talk about a variety of sex-related topics when they vaccinate nine-year-old to 15-year-old girls against HPV. The research indicated that physicians' intentions were high, but do not indicate how well physicians are prepared for this communication with nine-year-old to 15-year-old girls about sex. (Contains 4 tables.)