Age at menarche is a strongly heritable trait; in studies of twins 60%–80% of the variance is estimated to be genetic [9]. Despite recent identification of neuropeptide pathways involved in the activation of puberty, the factors that actually trigger this central process are still largely unclear [10]. There is a biological basis for a close link between nutritional status and the activation and maintenance of reproductive ability [11]. Factors that regulate infancy and early childhood growth, including genetic and epigenetic influences, could affect the timing of puberty [12]. We therefore hypothesised that mother's age at menarche may predict her offspring's early postnatal growth pattern and childhood obesity risk. We have examined this hypothesis in a large population-based birth cohort study: the Avon Longitudinal Study of Parents and Children (ALSPAC) [13].
