Large variation seen in how many relatives Swedes have

Relatives often play an important role in people's lives. Family members such as cousins, grandparents and grandchildren form part of an individual's social network and can provide significant support, ranging from child-rearing to elderly care to financial assistance.

In a new study Martin Kolk and a group of researchers at Stockholm University have documented for the first time how many relatives Swedes have. The study, "The Swedish Kinship Universe: A Demographic Account of the Number of Children, Parents, Siblings, Grandchildren, Grandparents, Aunts/Uncles, Nieces/Nephews, and Cousins Using National Population Registers," has been published in the journal Demography.

"There has been a lack of knowledge about how many kin people have in modern societies, and this information has never before been collected for an entire population. There have not been clear answers to questions such as how many cousins you have in Sweden or other countries," says Martin Kolk, Associate Professor in Demography at Stockholm University's Demography Unit and lead author of the study.

Sweden has unique registers

Research on family networks requires very large data sets that are of high quality and that go back far in history. The study uses Sweden's unique population registers which enables researchers to create kinship networks where individuals can be linked to all of their living relatives.

How many relatives you have in life is affected by which part of the life cycle you are in. Older people have many relatives in the descending line, such as grandchildren, and younger people have relatives in the ascending line, such as parents, while people in the middle of life also have many relatives in the same generation, such as siblings and cousins. Swedes in the middle of their lives have an average of eight cousins, and almost 30% have 11 or more cousins.

Of the types of relatives examined in the study (from grandchildren to grandparents), Swedes have an average of 20 relatives in their mid-30s, while young children have about 15 relatives, and 70-year-olds about 10.

"How many relatives you have is affected by many different things, such as differences in childbirth over time, when in life you have children, differences in life expectancy, and age differences between partners. All of these things can differ greatly between different families, and have also changed a lot over time," says Martin Kolk.

Very rare with no relatives

Having no relatives at all in life is very rare, and only occurs in exceptional cases among very old people. The family networks of men and women are very similar. Over time, you see a higher proportion of relatives who are the result of separations, such as half-siblings.

"How many relatives you have differs very much between different individuals and at different ages. Most living relatives are found between ages 30 and 40. We see large variation in how many kin you have. The twentieth with the least kin have only 3–4 relatives, while the twentieth with the most kin have over 45," says Kolk,

Relatives important for life chances

"By documenting kinship we know more about a previously unexplored part of Swedish family life that is an important part of many people's lives. Social science research has also shown that relatives are more important for life chances in modern societies than previously thought, and therefore it is important to document how many kin people have."

"Sweden has the longest records of any country with modern digitized population registers starting in 1968, with parent-child links from 1932. The state has been collecting national population back to 1749. This is both very useful for administrating the Swedish welfare state, and also make internationally unique research possible, such as this study," says Kolk.

How the study was done

The study is based on Swedish register data, and includes all Swedish-born people who lived in Sweden in 2018. With the help of birth records, the researchers have created family networks and calculated the number of relatives such as grandchildren, children, nieces, nephews, siblings, cousins, parents, parents' siblings, and grandparents in Sweden through the unique Swedish national identity numbers. Using the register, the researchers have then calculated the averages and distributions of different categories of kin in Sweden.

Since there is only demographic data within Sweden's borders in Swedish register data, the study is focused on Swedish-born individuals. For individuals with foreign-born parents, grandparents are often missing. In the study, there are a number of figures showing the distribution and average number of kin of various types.