Educated fathers make better parents

How children affect parents' life expectancy

Do children make us live longer? Yes, say the numbers, but the reasons are many

Somehow there seems to be a connection between people's life expectancy and the number of their children: those who have a child generally live longer than childless people. If you have two children, you get a small life bonus. A new study with data from biological parents and adoptive parents examines what reasons there might be for this connection.

At first glance, the numbers seem clear: mothers and fathers generally live longer than childless people. The effect is even clearer for parents who adopt children: If a child is adopted, life expectancy increases by three years. With two or three children it is even five years. This is shown by a new study by Kieron Barclay from the Max Planck Institute for Demographic Research in Rostock and Martin Kolk from Stockholm University. To do this, they were able to draw on data from over four million Swedish women and men who were born between 1915 and 1960.

The relationship between the number of children and life expectancy is not new. And there are various theories about it. The special thing about the Rostock study is that Barclay and Kolk can also fall back on data from adoptive parents. This enables them to better separate physical and social causes from one another.

For example, a common theory is that women who have given birth are less likely to develop breast or uterine cancer. The data from Sweden, which includes health claims, also confirm this. At the same time, however, it is also very clear: biological fathers and parents with adopted children also generally have a lower mortality rate than childless persons (see Figure 1). And the curves for men and women are quite similar. Biological causes that target mothers and the physical consequences of childbirth can only be a very small piece of the puzzle.

Parent resources play a role

Another theory that uses the body as an explanation is refuted by the numbers alone. The so-called “disposable soma theory”, in English for example “theory of the disposable body”, assumes that women in particular invest their strength and health either in their reproduction - i.e. in children - or in their longevity. Because the mortality of both adoptive and biological parents is below that of childless at least up to the fourth child, Baclay and Kolk reject this explanation. At best, it could have been historically accurate when childbirth was a higher risk for women and the social and health services were significantly worse, the researchers write. They give similar reasons against the theory of “social exhaustion”, which emphasizes not the physical but rather the social and psychological exertion of parents.

Barclay and Kolk are much more likely to suspect that it is not the birth or the children that give parents a longer life expectancy. Rather, they suspect that parents were better off from the outset than those who do not have children. To put it in a somewhat simplified way: Those who have health, money and education are more likely to find a partner and also have the resources to start a larger family. These people then bring their mortality advantage with them from the outset - it would therefore be more of a requirement than a consequence of having children.

Adoptive parents benefit particularly strongly

In the case of biological parents, for example, it can be seen that their mortality comes much closer to that of the childless if the scientists take into account in the analysis what education or what occupation the respondents had (see Figure 1). In the case of biological fathers and mothers with one child, the mortality advantage disappears completely in this case; in the case of five or more children, biological parents then even have a lower life expectancy than childless people. Here, too, selection could play a role: in the past, parents with many children often had a rather low level of education, a low income and no favorable health behavior.

It looks different with the adoptive parents. You have already been positively selected because you will be examined very carefully during the adoption process: Your health, financial situation, home, contact and behavior will be checked. Therefore, Barclay and Kolk conclude, they also have a significantly lower mortality rate than biological parents who do not have to go through such a selection process (see Figure 1).

A closer analysis of the adoptive parents reveals the importance of this test (see Fig. 2). For example, the adoption of a non-Swedish child is subject to a much stricter test than the adoption of native children. While the parents of Swedish adoptive children have roughly the same mortality as biological parents, the mortality rate among adoptive parents of foreign children is much lower. In other words, only the healthiest, most stable and strongest people were selected from the outset.

Children increase life expectancy even among the more educated

The analysis of the different educational groups also shows a selection process (see Fig. 3). First of all, it meets expectations: the higher the education, especially of women, the lower the mortality among them. At the same time, the more children a woman has, the greater the advantage in the higher educational groups. While women without a high school diploma reach their highest life expectancy with two children, this is only the case with three children for women with a high school diploma. Among mothers with university degrees, however, those with four children can count on the longest life.

But selection alone cannot explain the differences between parents and childless people. As can be seen in Figure 1, the majority of parents, namely those with two, three or four children, still have an advantage over the childless when factors such as education and work are taken into account.

Barclay and Kolk explain this advantage in life expectancy with the fact that children have a positive influence on the health of their parents. There are two possible theories about this: On the one hand, children could later ensure that their aging parents receive support and help. For example, there have been studies that have shown that a high level of education and a high income for children go hand in hand with a longer life expectancy for their parents. In general, however, Barclay and Kolk could not find any evidence for this theory. Because then it would be expected that parents would benefit more from this support the more children they have. In fact, however, life expectancy in the biological parents only increases up to the second child and then decreases again (see Fig. 1).