Multiple associative studies consistently point in the same direction: a genetic predisposition for longevity exists and is measurable, but it accounts for less than half of the differences in health in later life. Environmental factors, including those present as early as in the womb, play an equally important role. In practical terms, this means that people with short-lived parents are not destined to follow the same path, but they do benefit from taking lifestyle choices seriously.
Yes, your life expectancy is partly determined by heredity, but only in part. Research on descendants of long-lived parents shows that people with at least one parent who reached the age of 90 scored 31% lower on a measure of health deficits (the so-called frailty index) than people whose both parents died before the age of 76. Statistically, it is estimated that approximately 39% of the differences in this health score can be traced back to genes. That sounds impressive, but it also means that well over 60% is determined by other factors.
Genetic research confirms this picture. People with a higher genetic predisposition for accelerated biological ageing (measured via an epigenetic clock called GrimAge) had parents who lived shorter lives on average. Genetic variants associated with a higher level of education also appear to correlate with a longer lifespan, suggesting that some genes influence how old you get through cognitive or behavioural pathways. Disease genes also play a role: people with a greater genetic predisposition for lung cancer statistically have shorter-lived parents. All of these associations are correlational in nature, not direct cause-and-effect evidence.
Biological ageing markers such as telomere length are also partly inherited. Longer telomeres from the mother and a higher paternal age were associated with longer telomeres in newborns. At the same time, however, it turned out that anxiety in the mother during pregnancy, smoking, blood sugar levels and vitamin B12 levels were at least equally relevant. Environmental factors even before birth therefore already leave their mark on biological ageing markers.
There is also evidence that environmental stress in parents can leave epigenetic traces that are passed on to offspring and may influence disease risk, a phenomenon known as transgenerational epigenetic inheritance. This research has so far been conducted primarily in insects as a model organism. The translation to humans is still scientifically uncertain and requires further research.
In summary: long-lived parents do confer a biological advantage, but genes are not destiny. More than half of the variation in health and lifespan is determined by lifestyle and environment, including factors that begin as early as in the womb. Smoking, blood sugar regulation and psychological stress during pregnancy already influence the biological ageing markers of the unborn child. If your parents died young, that does not mean you will share that fate, but it is a reason to pay extra attention to the lifestyle factors that are within your own control.
All claims are based on associative research (GWAS, cohort analyses, epigenetic studies). None of the studies provide direct evidence of causality for the total hereditary share of life expectancy. The heritability estimate of 0.39 is based on a single study (PMID 22986583). Transgenerational epigenetic inheritance in humans (PMID 25778758) remains speculative.