The disorder in question is Williams Syndrome (WS), which is a neurodevelopmental disorder due to the deletion of 26 genes from chromosome 7. Apart from a typical elfin appearance, one of the more remarkable symptoms is cheerfulness and an open demeanor to strangers.
The research shows that
[...] children with WS lack racial stereotyping, though they retain gender stereotyping, compared to matched typically developing children. Our data indicate that mechanisms for the emergence of gender versus racial bias are neurogenetically dissociable. Specifically, because WS is associated with reduced social fear, our data support a role of social fear processing in the emergence of racial, but not gender, stereotyping.
One caveat, as expressed in the account at NatureNews is that WS is associated with mental retardation, which may have an effect.
The study does not answer whether stereotyping is genetically determined or based on experience, Meyer-Lindenberg says. So he’d also like to examine the role of experience, for instance, by finding children who have been raised by two members of the same sex.
“Until this study, I think people never imagined that these two stereotypes would be biologically separable,” Gabrieli says. “Whether it turns out to be due to genes, the environment or a complicated interaction, it shifts the discussion.”
But to where would it shift the discussion?