Teens from larger families have poor mental health than those with less siblings, according to a large investigation of children in the United States and China.
The details of the pattern differ depending on factors such as the spacing of sibling ages and the age of the siblings.
Doug Downey, the lead author of the study and professor of sociology at The Ohio State University said that, the overall pattern was found in both countries is striking.
Our results couldn’t have been easily predicted before we did the study, said Downey. Other studies have shown that having more siblings is connected with some positive effects, so our results were not a given.
Downey conducted the study with Rui Cao, a doctoral student in sociology at Ohio State. Recently their results were published in the Journal of Family Issues.
Their Chinese study draws on more than 9,400 eighth graders from the China Education Panel Study. In the United States, they studied over 9,100 American eighth graders from the Early Childhood Longitudinal Study – Kindergarten Cohort of 1988.
The average youth in China has approximately 7 fewer siblingsthan the average American youth.
Consistent with what was expected because of China’s One Child Policy, about one-third of Chinese children are only children (34%), compared to just 12.6% of American children.
In both nations, researchers asked students (average age of 14) many questions about their mental health, though the questions were different in the United States and China.
Teens with no siblings showed the best mental health, in China while in the United States, those with one or no sibling had similar mental health.
Some issues could only be investigated using the U.S. data.
Results in the U.S. showed that half and full siblings are both connected to lesser mental health.
According to the US data, having older siblings and siblings closely spaced in age tended to have the worst effects on well-being, Siblings who were born within a year of each other had the strongest negative connection with mental health.
If you think of parental resources like a pie, one child means that they get all the pie, which means all the attention and resources of the parents, he said.
But when you add more siblings, each child gets less resources and attention from the parents and that may have an impact on their mental health.
The fact which closely spaced siblings have the most negative impact bolsters that explanation. Children who are close to the same age will be wanting the same types of parental resources.
Another possibility, though, is that the families that have many versus few children are different in other ways which may reduce mental health for their children.
The differences between China and the U.S. do provide some support for the selectivity explanation. In each country, children from families connected with the most socioeconomic advantage had the best mental health.
In China, that was children in one-child families, while in the U.S. it was children with non or one sibling.
But the total results still suggest that selectivity explanation falls short in accounting for what is happening.
What we realize was, that when you add all the evidence up, the effect of siblings on mental health is more on the negative side than the positive side, said Downey.
Downey noted that the data doesn’t get at the quality of sibling relationships. It is likely that higher-quality sibling relationships will be more beneficial to children and may have more positive effects on mental health.
While this study shows a negative impact of siblings, other research has shown that having more brothers and sisters is linked with better social skills among kindergarteners and a lower likelihood of divorce among adults.
This combination of results is not easily explained. We still have more to learn about the impact of siblings, said Downey.
Presently this is very important as the U.S. and other countries have lesser fertility rates. Understanding the consequences of growing up with less or no brothers and sisters is an increasingly important social issue.
