Ancient DNA says the adults and children in medieval graves were often strangers

Stockholm University’s Centre for Palaeogenetics sequenced the DNA of 142 people buried in Sweden between the late Viking Age and the Middle Ages, and the graves that held adults and children together mostly did not hold families. Lead author Maja Krzewińska said that close family is the usual assumption for adults and children sharing a grave, and that “in most cases” the DNA did not bear it out.

The paper, “Equal in death: Ancient genomic analysis of children’s early Christian burials,” appeared in Science Advances in 2026. Its question was what a shared grave meant when no grave goods survive to say.

Sigtuna, Västerhus and Fjälkinge

The three sites are Sigtuna near Stockholm, Västerhus in Jämtland and Fjälkinge in Skåne. Stockholm University’s own release, dated July 10, 2026, puts the sample at more than 60 children and adolescents among the 142. The paper’s abstract gives the full breakdown: 68 subadults and 74 adults, drawn from 27 single burials and 50 multiple burials. Live Science describes the material as skeletons from three cemeteries, which is the scale the kinship work rests on.

Early Christian burial leaves little to read.

The abstract notes that such contexts lack grave goods, and that children cannot be reliably sexed from their bones, so many studies of the past leave them out. Genomic sexing and kinship analysis let the team treat the children as individuals at these sites, with a sex and a set of genetic relatives attached to each one, instead of as an undifferentiated group.

The method has two stages, according to the abstract. The team first screened the genomes of all 142 individuals, which allowed genomic sexing of the children whose bones could not be sexed by eye, and then applied kinship analysis to individuals from the three sites. That sequence matters for reading the result: the sex of each child and the biological relationship between each child and the adults beside them came from the same ancient genomes, so the finding about strangers and the finding about gender treatment rest on one dataset and one set of burials from the late Viking Age to the Medieval period.

Rarely Related: The Proportion the Paper States

The paper’s own wording is “rarely.” The abstract says that, contrary to the assumption that collective burials reflect close kinship, “children interred with adults rarely shared close biological ties.” Krzewińska’s version, quoted in the university release, is “in most cases.” Neither source attaches a percentage to the full set of 50 multiple burials, and the abstract does not translate “rarely” into a count.

One figure does appear in Earth.com’s account of the work: at Västerhus, only about 1 in 8 collective graves with usable DNA contained close relatives, meaning a parent, child or sibling. That is a site-level number from a secondary report, not a rate for all three cemeteries.

“Strangers” is a plain-language gloss. What the paper establishes is the absence of close biological ties, which is not the same as proof that the dead were unknown to one another. The abstract itself says that “extended kinship likely played a central role in structuring these communities,” which leaves room for cousins, in-laws and neighbors in the same grave. News-Medical’s summary quotes the same point from the other side: close biological relatives were “surprisingly rare among people buried in the same grave, even at cemeteries where high levels of kinship could be detected.”

Lady 56 and the Scallop Shell

One burial is a counterexample. A woman called Lady 56, from Västerhus, was buried with a scallop shell, the symbol of the pilgrimage to Santiago de Compostela. DNA linked her to her parents, her brother and two daughters, all in the same cemetery but not the same grave.

Families were present in the churchyard and could be identified genetically, but they were laid out across the cemetery instead of together in one pit. The graves that held adults and children side by side were assembled on some other principle. The abstract’s answer points toward wider community ties rather than the household, and it notes that flexibility existed in how the dead were placed, so no single rule governed every grave at every site.

The gender results fit that reading. Professor Anders Götherström, a co-author at the Centre for Palaeogenetics, said of the children: “In death, they appear to have been treated according to the same social and religious principles as adult men and women.” The abstract adds that gender roles were established early, with both boys and most girls mirroring adult spatial patterns in the cemeteries.

Anna Kjellström, another co-author, framed the method as the real advance, saying ancient DNA had finally supplied the tool needed to test these interpretations directly. The exact share of related pairs across all 50 multiple burials is not stated in the abstract or in the university release, which is why the 1-in-8 figure from Västerhus is the only ratio on the public record, and why it carries its source in the text.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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