The aim of this study was to explore the contribution of biomechanical factors to the development and progression of knee osteoarthritis (OA) by investigating whether the offspring of subjects with medial tibiomfemoral OA demonstrate gait abnormalities in the absence of OA. Three-dimensional gait analyses were performed on 9 offspring of people with medial tibiofemoral OA and 9 age, gender and Body Mass Index (BMI) matched individuals with no parental history of knee OA. External knee adduction, extension and flexion moments, as well as the magnitude of foot rotation during early stance were compared between the groups. The offspring of people with medial tibiofemoral OA walked with less external rotation at the foot than control subjects during early stance (4.5 degrees versus 13.5 degrees, p < 0.01). There were no significant differences between groups for the peak knee adduction moments (dominant leg, p = 0.49; non-dominant leg, p = 0.70) or peak knee extension moments (dominant leg, p = 0.46; non-dominant leg, p = 0.48). Moreover, there was no difference between groups for the knee flexion moment occurring when the force adducting the knee was greatest (dominant leg, p = 0.35; non-dominant leg, p = 0.33). Although the offspring of people with medial tibiofemoral OA walked with less external foot rotation than the control subjects during early stance, whether this increases their risk of developing knee OA is yet to be determined.