The best behaved children are those with older parents, Dutch scientists say
Noting the increasing trend for many parents in Organisation for Economic Cooperation and Development (OECD) countries to have children later in life, a group of Dutch researchers considered the behavioural problems of children born to older parents, finding that the age of the parents had an impact on children’s externalised behaviours such as aggression and anger outbursts.
Looking at both externalising behaviours and internalising behaviours, such as anxiety and depression, of children born to older parents, researchers found that children of older parents tend to have fewer externalising behaviour problems than children of younger parents. The researchers also found that parents’ age was unrelated to children’s internalising behaviours.
The study, conducted by researchers from Utrecht University, Vrije Universiteit Amsterdam, Erasmus Medical Center, and University Medical Center Groningen, appears in Child Development, a journal of the Society for Research in Child Development.
Lead researcher Marielle Zondervan-Zwijnenburg, from Utrecht University, said the inspiration from the study was sparked by existing evidence pointing to an association between fathers’ age and autism spectrum disorders and schizophrenia.
Researchers then wanted to know if there is an association in the general population between parents’ age and common behaviour problems in children, beyond the clinical diagnoses, Ms Zondervan-Zwijnenburg said.
“With respect to common behaviour problems, we found no reason for future parents to worry about a harmful effect of having a child at an older age.”
Researchers analysed the “problem behaviour” of 32,892 Dutch children when they were 10 to 12 years old. Problem behaviour was rated by fathers, mothers, teachers, and the children themselves through a series of standardised instruments.
The children, all of whom were born after 1980, were part of four studies – Generation R, the Netherlands Twin Register, the Research on Adolescent Development and Relationships-Young Cohort (RADAR-Y), and the Tracking Adolescents’ Individual Lives Survey. The children represented the entire Dutch geographic region across all strata of society and a range of socioeconomic statuses.
- In the Generation R study, mothers’ age at child’s birth ranged from 16 to 46 and fathers’ age at child’s birth ranged from 17 to 68.
- In the Netherlands Twin Register, mothers’ age at child’s birth ranged from 17 to 47 and fathers’ from 18 to 63.
- In the RADAR-Y study, mothers’ age at child’s birth ranged from 17 to 48 and fathers’ from 20 to 52. And:
- In the Tracking Adolescents’ Individual Lives Survey, mothers’ age at child’s birth ranged from 16 to 44 and fathers’ from 18 to 52.
Children of older parents had fewer externalising behaviour problems, as reported by the parents. The findings of fewer externalising behaviour problems persisted – as reported by parents and teachers – even after considering the families’ socioeconomic status, so the researchers concluded that the favourable effect of parents’ age on children’s behaviour was not solely due to their income level. The study also found that parents’ age appeared unrelated to children’s internalising behaviour problems.
The study’s authors note that they focused only on children’s externalising and internalising behaviour problems, so the findings cannot be generalised to other behaviours – though they are extending their research to cognition and attention problems.
In addition, the researchers assessed children’s behaviour problems during early adolescence; they plan to extend their work to other points in development.
“It’s possible that some of the reasons why older parents have children with fewer problems like aggression is that older parents have more resources and higher levels of education,” explained co-author Dorret Boomsma, professor of biological psychology and behaviour genetics at Vrije Universiteit Amsterdam.
“But it is important to note that the higher average educational level of older parents does not completely explain the decreased levels of externalising problems in their children.”
To read the study in full, please see here.