The precision that genetics provides was not available from the bones themselves.

So the sex finding, absolute in the genetic data, was the first thing the ancient DNA told the world that nothing else could have established with the same certainty.

Sixty-four genetically male children, held in an underground limestone chamber near the heart of one of the Maya world’s most important cities.

And then kinship analysis changed the picture again.

Researchers examined the genetic data for signals of biological relatedness among the 64 individuals.

What they found was that 11 pairs of the analyzed children showed evidence of being close relatives — first-degree or second-degree relatives — based on the patterns of DNA they shared.

Among those 11 pairings, two were something even more specific: pairs of monozygotic twins.

Identical twins.

Two sets of them, in the same subterranean burial, from the same archaeological context at Chichén Itzá.

The statistical improbability of that is worth pausing on.

Identical twins occur in roughly three to four births per thousand in populations that do not use modern fertility treatments.

Finding one pair of identical twins among 64 individuals is already notable.

Finding two pairs in the same archaeological assemblage, in the same specific location within a major ceremonial city, raises questions that genetics can identify but cannot, by itself, answer.

Who were these children?