A new study suggests that genetics may play a much larger role in determining human lifespan than previously believed, with up to 55% of the variance in longevity attributed to inherited traits. Researchers analyzed historical data from twin studies and adjusted for factors such as deaths from accidents and infectious diseases, finding that genetic makeup still accounts for about half of life expectancy. The study's lead author emphasized that while genes are significant, lifestyle and other factors remain important in shaping how long people live. Experts caution against adopting a fatalistic attitude, stressing that healthy choices can still influence individual outcomes.