Abstract Objective To assess the relationship between the oral literacy demand of genetic counseling sessions and the ability of low literate subjects to learn genetics-related information. Methods Ninety-six simulated genetic counseling sessions were videotaped and shown to 312 subjects recruited to imagine themselves as the session's client. Study measures included oral literacy demand, operationalized as: (1) use of key genetics terms; (2) informational context; (3) general language complexity; and (4) structural characteristics of dialogue interactivity. The study outcome was learning of genetics-related information. Results Subjects with restricted literacy (below 8th grade level) learned more when viewing sessions with greater dialogue interactivity and more personally contextualized information. Subjects with adequate literacy skills, however, tended to learn less in low literacy demand sessions. Conclusion The oral literacy demand of medical dialogue represents a learning obstacle to low literate subjects. However, this may not be the case for those with greater literacy skills who can understand the complex language and process the dense informational load of high demand sessions. Practice implications In order to meet the educational needs of all patients, clinicians must attend to both the informativeness and the oral literacy demand of their communication.