Early puberty may lead to the development of several different types of cancer in both men and women. This project aims to find out whether this increased cancer risk is partly due to adverse effects of early puberty on metabolism. To do this, we will examine links between genetic predispositions for timing of puberty and markers of body fat, along with a wide range of detailed blood-based markers of metabolic functioning. Data on ALSPAC mothers and children are particularly useful for seeing how genetic predispositions to early puberty affect fat and lean mass differently, and how these affect metabolic functioning at different stages of sexual maturity. Data on men from a separate cancer-specific study will also be examined to see how development of cancer affects links between puberty timing and metabolism. All results will be compared with those obtained from a separate analysis of genetic predispositions for puberty timing on metabolites using larger-scale collaborative data.