The most incisive guide to issues facing the American family today . . . An invaluable resource for anyone wishing to stay on the cutting edge of research on family trends.

-W. Bradford Wilcox
Associate Professor of Sociology, University of Virginia 

Grandparents: Catalyst of Family Growth

Bryce J. Christensen and Robert W. Patterson

Alarmed by the consequences of low fertility, policymakers in many developed countries have struggled to find ways to reverse the dynamics of de-population. A study in the Netherlands suggests that getting grandparents involved in caring for their grandchildren holds promise in increasing the number of those grandchildren.

Evidently concerned about “low birth rates in developed societies,” a team of researchers at Vrije Universiteit Amsterdam (VUA) set about investigating the issue. After all, they point out, “societies with low fertility face the risk of a shrinking working population” and, as a consequence, have reason to worry about “the sustainability of collective pension, social insurance, and care systems.”

These worried scholars begin their research with doubts about whether their colleagues were looking at the right issue in focusing on “the role of formal childcare” in helping women combine employment and motherhood. “Evolutionary theory points to the importance of kin,” these scholars assert, invoking a “cooperative breeding hypothesis” that emphasizes the way “the wider kin group has facilitated women’s reproduction during our evolutionary history.” These researchers see the critical role the wider kin network has played in supporting reproduction in pre-industrial societies, but acknowledge the lack of “direct evidence of beneficial effects of kin’s support on parents’ reproduction in modern societies.”

Such evidence emerges, however, from the VUA researchers’ careful scrutiny of data collected in two rounds of surveys between 2000 and 2002 from a nationally representative sample of Dutch men and women ages 54 to 84. These data clearly indicate that “childcare support from grandparents increases the probability that parents have additional children in the next 8 to 10 years.”

The fertility-enhancing effect of grandparental involvement in caring for grandchildren is quite pronounced. The researchers calculate that, with typical background variables, the child who is not cared for by grandparents would only see an addition to his family during the eight-to-ten-year period of interest in 35 percent of the cases. In contrast, the child who is cared for by grandparents would see an addition to his family in 66 percent of the cases.

In commenting on the fertility-enhancing effect of grandparental child care, the researchers reason that “in addition to providing practical support, such as childcare, grandparents can also encourage their children to reproduce. Grandparents can communicate that they would welcome grandchildren, and that they would like their children to become parents. Such normative social influence may also have a positive effect on the fertility of the children.”

The plausibility of such reasoning grows stronger in light of a prior study establishing that a German woman is more likely to bear a child if she lives in the same town as her parents than if she does not. Likewise supportive of this thinking is an Italian study showing that women have higher fertility if their parents are still living than if they are not.

The Dutch researchers further interpret their findings as support for neo-Darwinian theorizing, suggesting that the reason that “grandparents . . . enhance the reproductive success of their children” is that “relatives share common genes by descent.” Such common genes give biological logic to “natural selection . . . favor[ing] genes that enable individuals to help their relatives to reproduce successfully.” American readers may demur on the neo-Darwinian logic. But the power of extended family to foster fertility is very clear.

(Ralf Kaptijn et al., “How Grandparents Matter: Support for the Cooperative Breeding Hypothesis in a Contemporary Dutch Population,” Human Nature 21.4 [December 2010]: 393–405.)