Study suggests that having children impairs the cognitive health of parents 

On 22 May, Spanish newspaper Levante[1] reported a study conducted by Columbia University’s Mailman School of Public Health and Paris-Dauphine University. The study, published in the scientific journal Demography[2], claims that having three or more children hastens the cognitive decline of parents — both men and women — by up to 6.2 years when they become older. This effect allegedly has to do with the economic effort, the impact on work and the stress involved in parenting.

We can only imagine the founder of this Observatory, Dr. Justo Aznar (father of 10 children), questioning these claims from the heaven to which he departed in old age, having researched and published until the day of his departure with cognitive skills that most researchers we know would envy, both those “with” and “without” children.

Interestingly, the study adds that this effect is more pronounced in northern Europe, where the social resources available to families do not correspond to their size. Thus, more children mean more expenses and responsibilities, but not more social assistance. It does not say, however, that this assistance is higher than that offered in the countries of the south, so that household economies in northern countries do not suffer with the arrival of a new child — not even close — as they do in the latter.

It might be thought, therefore, that it is devious to blame high fertility for cognitive impairments in old age and that it is nonsense to consider the fertility of families as a possible predictor of cognition in old age, along with other factors such as education or occupation. What impairs health, including mental and cognitive health, is the stress and anxiety arising from insecurity and socio-economic vulnerability, factors that have to do more with political priorities than with family size.

The biases of the survey from which this conclusion was drawn

The researchers analyzed data from the Survey of Health, Aging and Retirement in Europe (SHARE)[3]. SHARE is an international and interdisciplinary project, promoted by a consortium of scientists from the European Union and the United States in response to the European Commission’s request to “examine the possibility of establishing, in cooperation with Member States, a European longitudinal aging survey” to promote European research on the aging process.

The data collected by SHARE include different health variables such as self-perceived health, physical and/or cognitive functioning, and use of healthcare services, as well as data on biomarkers such as body mass index, grip strength, and those that can be analyzed in a dried blood sample. It also includes variables related to psychological health, wellbeing and satisfaction, socioeconomic variables such as possible post-retirement work activity, the sources and composition of income, wealth and consumption, housing and education. Finally, it also includes variables on social support such as family care and assistance.

It is important to note that the results were obtained after applying a series of surveys that are international in nature (identical in content and format for participants from 27 European countries plus Israel), longitudinal (the same participants over time, who undergo hour-long interviews every two years) and interdisciplinary (because they cover a large number of variables that are rarely found in the same survey,  which allows for a comprehensive view of the situation of the interviewees and to explore the interaction between areas generally studied separately). Specifically, 140,000 people aged 50 and over have been followed up and have already completed approximately 380,000 interviews. Their answers have been analyzed with advanced econometric methods, which are presumed to be able to unravel the causality of their simple associations.

To the fact that the data come from surveys (often with items of self-perception and therefore with a significant subjective bias) and that their analysis is statistical (ignoring, consequently, that certain answers may be due more to the design of the question than to objectifiable evidence), it should be added that the project — as could not be otherwise — has a sponsor:  the European Commission through the Fifth, Sixth and Seventh Framework Programmes and Horizon 2020 and, additionally, the US National Institute on Aging. By their very nature, these institutions bring together the interests of European countries, which are expressed in the means and funding they provide from their state budgets.

In particular, in Spain, the funds allocated to it are managed by the Ministry of Science and Innovation (with its corresponding ideological bias) and by the Bank of Spain (with its corresponding economic bias). In each participating country, in fact, there is a scientific node, usually associated or affiliated with an academic institution, which is responsible for the implementation and monitoring of the survey in that country. In Spain, the Spanish scientific partner responsible for the management, development and monitoring of the survey since the first wave is the CEMFI (Center for Monetary and Financial Studies), an institute founded by the Bank of Spain dedicated to postgraduate training and research in economics. The professor responsible for the Spanish scientific team at CEMFI is Pedro Mira.

Finally, it is curious that the central coordination of the survey is assigned to Axl Börsch-Sipan, professor at the Munich Center for the Economics of Aging (MEA) at the Max Planck Institute for Social Law and Social Policy. The total bias of this study, therefore, is economic.

Suggested causes for cognitive impairment as a consequence of large families

The study says that, starting with the third child, having one more child usually involves:

  1. A considerable financial cost.
    1. Due to the costs derived from child-rearing.
    2. Due to the reduction in household income by having to reduce the hours of paid work to care for the offspring. Moreover, this situation particularly affects women, who are less likely to enter or remain in the labor market, or who have fewer hours worked and lower incomes.

As a consequence — adds the original study and underlines the newspaper owned by the PRISA group — the likelihood of falling below the poverty line increases, the standard of living for all family members decreases and financial worries and uncertainties are generated that could contribute to subsequent cognitive decline.

  1. Having children is a stressor
    1. It affects health risk behaviors.
    2. Parents with more children have less time to relax and invest in cognitively stimulating leisure activities.
    3. This may involve sleep deprivation for the father or mother, with the subsequent impact on health.

Perhaps not everything is bad…

Fortunately, the study does not hide the fact that large families generally lower the risk of social isolation among older people, which is a key risk factor for cognitive decline and dementia, and often increases the level of interaction and social support, which may be protective against cognitive decline at older ages.

Our ethical assessment

That fact that living carries with it an associated dramatic burden is indisputable. For people, in fact, it is not enough for us to live; rather, we must “learn to live” by conquering our freedom — in a constant struggle against the egocentric conditioning of our instinctive nature and against the pressures of a sometimes hostile social environment — in order to be able to choose the ends and means that will allow us to achieve what we really yearn for: our personal fulfillment and completion[4], to the realization of our life. This conquest is impossible without the help of the virtues: prudence, which helps us to choose the good after proper deliberation; justice, which moves us to seek a good that is only good when it is common, that is, of each and every one; fortitude, which allows us to resist the pressures of the environment and the era; and temperance, which cools irrational impulses and encourages decisions that are not as cold and cerebral as those of artificial intelligence.

Turning parenthood into a decision to be made after a utilitarian calculation is typical of statistical software, in effect, of an artificial intelligence but not a human moral agent, which does not act for invariably physical and necessary causes, but for good reasons of conscience. These reasons compel us to seek good and avoid evil by taking into consideration certain principles that this study does not seem to address, such as the value of human life or the principle of justice itself.

However, this is not the place to dwell on considerations so profound in their weight and so extensive in their development. We shall simply say that:

  1. The study described herein is limited to correlating information obtained in a series of surveys that evaluate the self-perception of the subjects interviewed, and this detracts from its objective value.
  2. It shows a clear economic bias, which is due to its funding and the agencies responsible for interpreting the data. That financial hardship affects health is something we already know, but concluding that children are an economic problem and therefore a health problem seems to us to be ill-intentioned. Children can be received as luck, as a gift, as a joy; the news of their conception can frighten us, be considered an unforeseen event or make us shed a tear; they are certainly a responsibility; also, and above all, in normal conditions, they are the product of love… they can be many things but, of course, they are not a financial asset or a budgetary item.

It is striking, in this regard, that the study unashamedly admits that the decline in the cognitive health of parents is more pronounced in northern Europe, where the social resources available to families do not correspond to their size. Thus, more children mean more expenses and responsibilities, but not more social support. It seems shameful to appeal to the economic difficulties associated with child-rearing experienced by parents of the countries of northern Europe when, as evidenced by all the available data (and underlined by former director of the Earth Institute at Columbia University [2002-2016] and special adviser to the United Nations in relation to the Millennium Sustainable Development Goals, Dr. Jeffrey Sachs), it is the poor countries that cannot supply infrastructure to a population that doubles every generation, generating fiscal challenges to maintain their development that imply the “extension of capital” instead of its “deepening”[5]. In these countries, the size of the family could force the downsizing of agricultural plots and pastures, depleted by the lack of fallow land, and force the search for new resources such as deforestation and aquifer exploitation, adding, even more so if possible, to the poverty of those responsible for child-rearing. That, we dare say, is stress, not that of a couple in a Nordic state who are forced to bear the economic burden of raising a new child.

  1. It follows from the above that, for transnational political bodies, the large family has always been a problem in any context: in rich countries, because social aid is not in line with the size of families, while in developing countries, it has been argued that too young and poor a population poses risks to international security and causes irreversible damage to ecological sustainability[6]. Since the 1960s, theorists such as Garrett Hardin have claimed that ruin is the destination to which all men run if freedom of procreation is preserved, which would constitute something like an attack on common resources[7]. More apocalyptic, if anything, were the Paddock brothers[8] and Paul Ehrlich[9], for whom it is not a question of how many people fit in reasonable conditions on the planet, but of how many we can populate it with living as kings. In the late 1970s, Ehrlich wrote a book with John Holdren, who would become a science and technology advisor in the Obama administration, in which he suggested the desirability of controlling the size of the population: sterilizing the population by adding drugs for infertility in water and in the food supply; legitimizing “forced abortions” after the second child; introducing a license to have children and care for them effectively; undertaking the permanent sterilization of those who have already had many children or contribute to the “general deterioration of society”; passing laws that criminalize having more than two children; and monitoring compliance with these rules through transnational organizations, a global or planetary police[10].
  2. It is not difficult to assume that reducing the size of families may result in the selection of “defect-free” children. In fact, the conditions of race and health are already determinants in many surrogacy contracts[11].
  3. On the other hand, utilitarianism’s calculations of futurables are mere baseless fantasy. The survey’s advanced econometric methods aim to anticipate the long-term consequences of numerous offspring on the cognitive health of parents. However, to perform these calculations, they accept unsubstantiated assumptions, such as being able to know all possible states of the world that may arise at any time after each of our decisions, including whether or not to have one more child. To know this, we should be able to anticipate all possible global developments in the cosmic process, which is impossible, as well as to anticipate how others will react to each of our acts, because their consequences really depend on it. How might it affect our children to know that, if they were born, it is only because they did not prove burdensome to us? How will they assimilate that, for their parents, their cognitive health in old age is more important than their (the child’s) own life or that of their eventual unborn siblings? How will it affect parents, from a moral, social and psychological perspective in the medium and long term, to pay more attention to their own well-being than to the life of a child? What good does it do for a man to consider the child as a personal project, acceptable to a greater or lesser extent by budgetary criteria, than as the fruit of the loving encounter of his parents, as a good that counts for itself, a unique being that is someone and not something, a who and not a what to accept or reject? How happy are parents who are open to life and how does that happiness contribute to their life expectancy?
  4. The calculations referred to in the study call for better and more substantial support for parenthood, not its curtailment.
  5. The utilitarian calculation also seems to forget that there are biological and not just psychosocial consequences that make motherhood a benefit to the health of the expectant mother. These include the presence of so-called pregnancy-associated “progenitor cells” in the maternal blood in a ratio of 2 to 6 cells per milliliter. These progenitor cells are, in fact, stem cells from the blood of the fetus and the placenta that pass into the maternal circulation. Because they are pluripotent, these cells are replicated according to their own genetic code and can produce any type of cell, including epithelial cells. The presence of these fetal cells in maternal tissues and vice versa, i.e. the coexistence in a single individual of two cell populations originating from genetically distinct individuals, is called fetal microchimerism. However, the importance of fetal microchimerism is its role for the health of the mother, being able to affect her recovery after an injury, a transplant and some diseases[12]. These cells of the child, therefore, could pass to its mother to save her if need be. Moreover, that capacity persists for decades, and is not limited only to the exchange between the pregnant woman and the child. Some cells of older siblings and the maternal grandmother could also be transferred to the fetus because they had been incorporated, at the time, into the mother’s body[13],[14]. There seems to be no other way to describe this transaction of progenitor cells — which is greater the higher the number of offspring — than as a great benefit to the mother’s health.
  6. Appealing to demographic criteria, there are many objections that can be raised to the claim of the decline in cognitive health of parents of large families. First of all, if economic factors affect it, as the study repeatedly points out, we should not forget the demographic bonus theory. According to the latter, those countries in which a considerable proportion of their population is young will boost economic growth as a result of the higher proportion of workers, the rapid accumulation of capital and the sharing of dependency costs among a larger number of taxpayers.

Secondly, the reduction in birth rates has seriously compromised generational replacement, plummeting the West — and, it could be said the entire world based on demographic data updated by the World Bank[15] — into an unprecedented demographic winter with predictable consequences, among which are:

  • Less active and older population. Extension of the retirement age. This does not seem very helpful for the health of older adults.
  • Imbalances and shortfalls in public funds due to the diversion of funds towards the payment of pensions.
  • Imbalances in household investment and savings due to the increase in social taxes. This, in turn, will make it difficult to sustain private pension plans at a particular level in the face of the foreseeable reduction in public funds.
  • Decrease in disposable income, due to delay in receiving the inheritance or to spending it to support those from whom it is expected.
  • New economic challenges due to increased health and pharmaceutical spending.
  • Imbalances in the family structure due to the cohabitation of three generations.
  • Housing problems.
  • Shortage of healthcare professionals.
  • Increasing number of “really old people” (85 years and older).
  • All of the above said will probably result in a resurgence of campaigns that present euthanasia as a moral or social duty.

Graph. 1.

Population pyramids of the European Union between 2016 and estimated in 2100 (% of the total population).

Source: Eurostat (online data codes: proj_18np).

In Figure 1, the population data for 2018 are highlighted in solid colors, while the population forecast in the European Union for 2100 is shown as horizontal lines with no background. As can be seen, the number of adults of working/contributing age decreases as a result of falling birth rates. Given that life expectancy is increasing, what these data predict is either a decrease in contributions – which would be detrimental to the health and wellbeing of older adults – or an increase in the tax burden on workers that would contribute to the pensioner’s self-perception as a burden on the community, as a liability, while generating stress on the taxpayer that, for sure, would have a long-term impact on their cognitive health. It seems, therefore, that the demographic winter is certainly more harmful to the population than the selfless rearing of large families.

Figure 2. Population structure in the European Union by age between 2019 and estimated 2100 (% of total population)

Source: Eurostat (online data codes: demo_pjanind and proj_19ndbi)

Figure 2, in line with the information provided by the first graph, shows the progressive increase in the percentage of the older adult population and the alarming decline in the working-age and pediatric population who, when the day comes, will have to replace it. This situation, in terms of social benefits, is literally suicidal.

In view of the above, we believe that it is necessary to demand more argumentative and scientific rigor before venturing to make statements such as those suggested by the study reviewed and disseminated by Levante.

Enrique Burguete

BIoethics Observatory – Institute of Life Sciences

Catholic University of Valencia



[2] Does Childbearing Affect Cognitive Health in Later Life? Evidence From an Instrumental Variable Approach. Eric Bonsang; Vegard Skirbekk. Demography 9930490. DOI:


[4] MELENDO y MILLAN-PUELLES, Dignidad: ¿una palabra vacía?, Eunsa, 1996, pp. 56- 61

[5] SACHS, J. D. (2008) Commonwealth: Economics for a Crowded Planet. New York, The Penguin Press.

[6] Idem

[7] HARDIN, G., «The Tragedy of Commons» en Science, v. 162 (1968), pp. 1243-1248.

[8] Paddock, W., Paddock, P. (1967). Famine – 1975! America’s Decision. Who Will Survive? Boston: Little, Brown and Company

[9] Ehrlich, P. (1968). The population bomb. New York. Ballantine Books.

[10] Ehrlich, P.; Ehrlich, A.; and Holdren, J. 1977. Ecoscience: Population, resources, environment. San Francisco, CA: Freeman.

[11] Burguete, E.: “Revolución sexual y neovitalismo. Los servicios gestacionales en la reconfiguración social, como reproductoras, de las personas queer”, Cuadernos de bioética, 2019, vol. 30, núm. 99, pp. 159-170.

[12] O´Donogue, K.: “Fetal microchimerism and maternal health during and after pregnancy”, Obstetrics Medicine, 2008, vol. 1, núm. 2, pp. 56-64.

[13] Boddy, A., Fortunato, A., Wilson, M., & Aktipis, A.: “Fetal microchimerism and maternal health: A review and evolutionary analysis of cooperation and conflict beyond the womb”, Bioessays, 2015, vol. 37, núm. 10, pp. 1106–1118.

[14] Baldessari, M.: “Subrogación y pobreza”, cit., p. 341.




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