What parent hasn’t heard their child asking for a little brother or sister? It’s an opportunity for the child to gain a playmate and lifelong companion, with whom to share their joys and sorrows.
However, there are not only advantages to sharing parents, as reported in a new study by researchers at Ohio State University – the researchers investigated the impact of siblings on teenagers’ mental health, and their findings are surprising, to say the least.
Unusually, this research was carried out in two distinct countries – China and the United States – where family and demographic policies differ considerably. Both analyses were based on teens aged 14 on average.
The first, conducted in China, included over 9,400 adolescents from the China Education Panel Study, while the second involved over 9,100 adolescents from the Early Childhood Longitudinal Study. All were asked to complete a questionnaire about their mental health, but the questions differed from country to country.
Published in the Journal of Family Issues, the studies reveal that Chinese teens have an average of 0.89 siblings, far fewer than American teenagers (1.6). According to the figures, over a third of Chinese participants are single children, compared with just 12.6% of US teens, which is hardly surprising in light of China’s one-child policy.
The findings are far more surprising: they reveal that single children have the best mental health in China. And, contrary to what might be expected, the results are identical – or almost identical – in the US: single children were found to have similar mental health to teenagers with just one sibling, but levels of wellbeing decline as the family grows.
In this respect, the study highlights that siblings or half-siblings are associated with poorer mental health in the US.
“Our results couldn’t have been easily predicted before we did the study. Other studies have shown that having more siblings is associated with some positive effects, so our results were not a given,” says lead author Doug Downey, professor of sociology at Ohio State University.
“The fact that the overall pattern was found in both countries is striking,” he added.
Smaller slice of the pie
Another finding of the study is that the impact on teenagers’ wellbeing is worse when they have older siblings, or when siblings are close in age. The effect is even greater when siblings are born less than a year apart. This can be explained in part by the “dilution” of parental resources brought about by living in a large family.
“If you think of parental resources like a pie, one child means that they get all the pie – all the attention and resources of the parents. But when you add more siblings, each child gets fewer resources and attention from the parents, and that may have an impact on their mental health,” Downey suggested.
“Another possibility is that the families that have many versus few children are different in other ways that may reduce mental health for their kids – the so-called ‘selectivity explanation’. In the US and China, children from families associated with the most socioeconomic advantage had the best mental health.”
However, the researchers did not focus on the quality of relationships between siblings, which could considerably change the situation and even transform this negative impact into a positive one. This is a factor to be taken into account in further research.