Negative Effects of Paternal Age on Children's Neurocognitive Outcomes Can Be Explained by Maternal Education and Number of Siblings

Ryan D Edwards,Jennifer Roff

doi:10.1371/journal.pone.0012157

Ryan D Edwards, Jennifer Roff

Open Access

https://doi.org/10.1371/journal.pone.0012157

Copy DOI

Abstract

BackgroundRecent findings suggest advanced paternal age may be associated with impaired child outcomes, in particular, neurocognitive skills. Such patterns are worrisome given relatively universal trends in advanced countries toward delayed nuptiality and fertility. But nature and nurture are both important for child outcomes, and it is important to control for both when drawing inferences about either pathway.Methods and FindingsWe examined cross-sectional patterns in six developmental outcome measures among children in the U.S. Collaborative Perinatal Project (n = 31,346). Many of these outcomes at 8 mo, 4 y, and 7 y of age (Bayley scales, Stanford Binet Intelligence Scale, Graham-Ernhart Block Sort Test, Wechsler Intelligence Scale for Children, Wide Range Achievement Test) are negatively correlated with paternal age when important family characteristics such as maternal education and number of siblings are not included as covariates. But controlling for family characteristics in general and mother's education in particular renders the effect of paternal age statistically insignificant for most developmental measures.ConclusionsAssortative mating produces interesting relationships between maternal and paternal characteristics that can inject spurious correlation into observational studies via omitted variable bias. Controlling for both nature and nurture reveals little residual evidence of a link between child neurocognitive outcomes and paternal age in these data. Results suggest that benefits associated with the upward trend in maternal education may offset any negative effects of advancing paternal age.

Highlights

The demographic transition has brought declining fertility rates and population aging across the industrialized world [1]
Results suggest that benefits associated with the upward trend in maternal education may offset any negative effects of advancing paternal age
An array of studies have shown advanced paternal age to be associated with neurological disorders, especially schizophrenia [8,9], and a recent study [10] reveals a negative association between paternal age and children’s neurocognitive outcomes in US data from the 1960s and 1970s

Summary

Introduction

The demographic transition has brought declining fertility rates and population aging across the industrialized world [1]. A companion piece [11] discusses the implications and the robustness of the findings, focusing in particular on how the negative effect of father’s age becomes somewhat attenuated once family socioeconomic status is controlled. This result is somewhat puzzling given that one would expect paternal age to be positively associated with family income and wealth, and for the latter to be positively associated with child outcomes. Recent findings suggest advanced paternal age may be associated with impaired child outcomes, in particular, neurocognitive skills Such patterns are worrisome given relatively universal trends in advanced countries toward delayed nuptiality and fertility. Nature and nurture are both important for child outcomes, and it is important to control for both when drawing inferences about either pathway

Objectives

Methods

Results

Discussion

Conclusion