This paper examines the development and consistency of children's (4, 7, 10, and 14 years) naïve concepts of inheritance using three tasks. A modified adoption task asked participants to distinguish between biological and social parentage in their predictions and explanations of the origins of different feature types (physical characteristics, disabilities, and personality traits). The causal mechanisms task asked participants to rate their preference for various mechanisms of inheritance for physical features. The family relatedness task required participants to provide judgements on the relatedness of family members and explain their understanding of kinship terms. Developmental trends were revealed in all three tasks. There was a trend towards increased consistency in judgements across tasks with age, but low correlations between explanations given in different task contexts. Findings are discussed with reference to the onset and variability of inheritance concepts and the implications for education and future research.