Daphne Garrido
Preprint · September 2026 - Preprint on Zenodo
Genetic Contributions to Gender Diversity.pdf
Identical twins offer geneticists something close to a natural experiment.
They share nearly all of their DNA sequence. Fraternal twins share substantially less, on average. If identical twins resemble each other more strongly for a particular characteristic, researchers can use that pattern to estimate whether genetic variation contributes to differences across a population.
Apply that logic to gender-related characteristics and an intriguing signal appears.
Genes probably matter.
Then comes the difficult part.
Scientists have looked directly at DNA for the molecular architecture underlying that signal.
So far, they have not found a simple answer.
The distance between those two observations—evidence compatible with heritability, but no mature molecular explanation—is the central problem examined in Genetic Contributions to Gender Diversity.
Heritability is among the easiest concepts in genetics to misunderstand.
A heritability estimate describes variation within a population under particular conditions.
It does not mean that a corresponding percentage of one person's identity was “caused by genes.”
It does not identify a particular gene.
It does not imply that a characteristic cannot change.