New resting-state functional connectivity-fMRI methods coupled with AI machine learning were used on humans.
One outlier was in the right precuneus cortex, which lies in the parietal cortex in the back half of the brain. The precuneus is connected to brain regions that process visual and pheromonal stimuli as well as sexual arousal. Thus, it seems plausible that the precuneus, in combination with the prefrontal cortex, is involved in processing aspects of sexual orientation.
Previous studies in male subjects have speculated that the connectivity patterns observed are the result of genetic factors. In contrast, no significant genetic linkage has been discovered with regard to female sexual orientation. Overall, genetic differences do not appear to be involved in sexual orientation. No genome-wide association studies, comprising genetic data from almost 500,000 individuals, has thus far lead to a meaningful prediction of an individual’s sexual orientation.