Background: A number of previous studies exploring family history of type 2 diabetes have reported a predominance of maternal diabetes. These studies have not explicitly compared parental history of diabetes across the spectrum of disease onset from youth to later adulthood.Methods: Family history data from 11,467 patients with type 2 diabetes were extracted from the RPA Diabetes Centre database. Parental histories of diabetes were compared across a range of age of diagnosis strata (15-<30, 30-<40, 40-<50, 50-<60 and 60-<70 years). For the young-onset group (diagnosed between 15 and 30 years of age), associations between parental history of diabetes and the presence of cardio-metabolic risk factors and diabetic complications were also explored.Results: For the total cohort and within each age of diagnosis strata, more individuals reported maternal history than paternal history of diabetes. The young-onset group demonstrated the highest prevalence of any parental history of diabetes (60.7%), the highest combined maternal and paternal history (15.8%) and the smallest differential between maternal (25.1%) and paternal (19.7%) history of diabetes. Within the young-onset group, no significant association between parental history and cardio-metabolic risk factors or diabetic complications were identified after a median of 15.0 years of diabetes exposure.Conclusion: Overall, our results demonstrate a consistent maternal excess of diabetes which could be consistent with an underlying epigenetic effect. However, the differential between maternal and paternal history is significantly lower in the young-onset group. Earlier emergence of type 2 diabetes may therefore reflect a different interaction and impact of genetic and environmental factors. [ABSTRACT FROM AUTHOR]