Childless men and women have an overall higher mortality than adults with children, meaning that they die earlier, recent studies show. Mothers and fathers with two biological children have the lowest mortality risks, but it increases for parents with three or more biological children. What are the explanations for the relationship between having children and mortality risks? In a new study, researchers Kieron Barclay and Martin Kolk try to detangle the physiological and social explanations for this relationship.
Barclay and Kolk compared the mortality of adoptive parents with the mortality of biological parents. They used register data from Sweden, examining mortality amongst men and women born between 1915 and 1960. All individuals in the data have reached so-called completed fertility, which means that the individuals in the analysis are all over the age of 45.
The authors conclude that so-called selection based on socio-economic status or health plays a big role in explaining the differences in mortality when comparing childless individuals with parents. In this case, selection refers to the fact that childless people differ from the whole population – not because they do not have kids, but because of other, underlying factors, of which some are known and some are unknown. For example, some individuals may have poor health, and at the same time have trouble finding a partner. This may explain why childless individuals have higher mortality.
People who have many biological children have higher mortality than those with only two children, which may also be due to selection - they might come from groups that have less healthy behaviour and habits in general.
The results of the study show that adoptive parents always have lower risks of mortality than parents with biological children. For parents that adopt children transnationally, the researchers find that the more children they have, the lower their mortality risk.
They also found that deaths due to accidents and other external factors are higher among individuals with no children compared to parents. The higher mortality for childless individuals could therefore be connected to harmful behaviour related to health and childlessness.
The researchers additionally found that childless women have the highest risk of breast cancer, which is in line with previous research. Having more children even reduces this risk. For biological mothers, biomedical aspects may therefore be part of the puzzle.