Do our genes determine how old we get?

Each person's genetic predisposition influences the ageing process and thus their personal life expectancy. Previous studies have compared the lifespan of identical twins in humans and estimated the influence of genes to be around 10-15 percent [Melzer et al. 2020]. However, these values do not take into account the fact that people often die as a result of external influences such as accidents or infections (“extrinsic mortality”). A new analysis using mathematical models and data from twins who grew up together and separately corrects for this effect: If only deaths due to internal, biological causes (“intrinsic mortality”) are considered, heritability is over 50 percent [Shenhar et al. 2026].

Aging is therefore significantly determined by our genes as well as by lifestyle and external influences.

In some model organisms, genes are known to have a direct effect on life expectancy. In the worm Caenorhabditis elegans and in the fruit fly Drosophila melanogaster, the inactivation of certain genes even leads to a doubling of life expectancy [Piper & Partridge 2018, Tissenbaum 2015]. However, the fact that such life-extending gene mutations have not become widespread in nature suggests that the negative effects of the gene mutations outweigh the benefits of longevity.

Updated February 2026