This study aims to investigate genetic underpinnings of body composition among adults. By combining measures of total and regional body fat, lean, and bone mass with measures of common genetic markers among participating post-adolescents and mothers in ALSPAC, we aim to search for and describe specific genetic variants that may influence differences in body mass, and ultimately future disease, in a young and middle-aged adult population. Ultimately, this work will be combined with work done in other cohorts of similar-aged adults to increase the scope and reliability of results.