Genes May Set Half Your Lifespan, New Study Finds

New research suggests genetic factors account for about 50% (roughly 50–55%) of human lifespan, higher than previous estimates. Using twin simulations and real-world data, researchers show that extrinsic mortality and historical age cutoffs biased earlier heritability estimates downward; when corrected, heritability rises to about half. Scandinavian twin data and studies of siblings of centenarians corroborate the finding, pointing aging research toward identifying the specific genetic variants that govern longevity.