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More brothers – less chances for a college degree?

Study compares chances to obtain higher education in different European countries regarding number of siblings and gender inequality

(August 2016) Whether or not a young person is able to obtain a college degree depends on many different aspects.  However, previous research has shown that family background plays a key role in children’s educational achievements.  Studies imply that especially children growing up with many siblings have disadvantages in cognitive development and less success at school. While a father or mother can read out a book to all of their children at the same time, he or she usually cannot help all of them with their homework in the same way. Thus, time but also financial resources (e.g. for tuition fees) need to be split among the children – a phenomenon called resource dilution.

Parents do not always support sons and daughters in the same way

Researchers from the University of Amsterdam wanted to find out: Do children growing up with brothers have more disadvantages then those with sisters? Their study is based on data from 98,244 adult children taken form the Survey of Health, Aging and Retirement in Europe (SHARE) which was conducted in 18 European countries, thus facilitating international comparisons.
The researchers assumed that especially in traditional societies, parents might tend to favor their sons over their daughters due to cultural or economic reasons.  In countries with higher gender inequality such as Hungary, Greece or Poland (based on the Gender Inequality Index of the United Nations), parents might decide to invest more in the education of their sons, e.g. because they expect men to earn higher wages or because they consider their daughters’ marriage prospects more important than their schooling.

Every (additional) sibling reduces the chances to go to college

The study confirms that with a growing number of siblings, the number of adult children that successfully finished college decreased. For each additional child in the family, daughters’ odds to have a college degree declined with 19%.  For sons, this was nearly the same – their chances to go to college decreased by 18% with every additional sibling.
However, the gender of the siblings matters: The study showed that for women, the negative impact of brothers on their chances of going to college was 22% higher than that of sisters.
The educational achievements of sons also decreased with every additional sibling, but the effect was hardly stronger in case of having brothers. Additionally, the study showed that first-born sons and daughters have better chances to go to college then their younger siblings, while stepchildren have a lower probability to obtain a college degree.

Denmark or Hungary – a big difference for women

When comparing the 18 different countries where the data was collected, the negative effect of the number of brothers on college completion is clearly linked to the countries’ gender inequality: While it is very strong in Hungary, Estonia and Poland, women and men who grew up with brothers in the Netherlands, Denmark or Switzerland were less affected. The study did not find a similar negative effect for women or men with sisters. It showed, however, that sons growing up with siblings in countries with a high gender equality were slightly more affected by the resource dilution then those who were raised in very traditional societies.
In brief, the study shows that siblings’ gender configuration influences how parents foster the educational success of their sons and daughters. At the same time, these differences are influenced by the society and the gender climate of the country where the family lives.

Study by Matthijs Kalmijn, Herman G. van de Werfhorst (2016): Sibship Size and Gendered Resource Dilution in Different Societal Contexts. PloS one. DOI:


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