Life decisions leave a lasting biological imprint.
A study by researchers from the University of Helsinki has shown that both having more children than average and having none at all may be associated with a shorter lifespan and faster biological aging.
At the same time, the researchers emphasize that these findings should not be interpreted as individual health recommendations. They refer only to a statistical correlation at the population level, which aligns with current views in evolutionary biology.
The authors of the study attempted to obtain a complete picture of reproductive history. To do this, they analyzed data from 14,836 women, each of whom was a twin—this approach helped reduce the influence of genetic differences. Additionally, for a subgroup of 1,054 participants, the researchers assessed biological aging indicators. The participants were divided into seven groups based on the number of living children and the age at which they were born. Statistical analysis showed that the worst biological aging indicators and a higher risk of mortality were observed in women who had no children, as well as in those who had the highest number of children—on average, nearly seven children.
Women who gave birth at a young age also demonstrated signs of accelerated biological aging and shorter lifespan; however, this difference largely disappeared after accounting for other factors such as alcohol consumption and body mass index. Nevertheless, the negative effects for childless women and women with many children persisted even after adjusting for these factors. The best biological aging indicators and the lowest mortality risk were observed in women with an average number of children—about two to three—and in those who became pregnant between the ages of twenty-four and thirty-eight.
The disposable soma theory does not explain why childlessness is associated with worse outcomes. The researchers suggest that unaccounted factors, such as pre-existing health conditions, may simultaneously influence reproductive behavior and health in later life.
The team notes that a person biologically older than their chronological age has a higher risk of death. The study's results show that life decisions leave a lasting biological imprint that can be measured long before old age sets in. In some analyses, giving birth at a young age was also linked to accelerated biological aging. According to the researchers, this may align with the evolutionary theory that natural selection favors earlier reproduction, shortening the overall generation period, even if it comes with long-term health costs.
