Gay sexual preferences are surprisingly similar to those of straight men. By Leon F. Seltzer, Ph.D.
"It might be that by the time males are born, a binary ‘gender cue’ in their brain software gets set to target either masculinity or femininity. There is some evidence that a neural network consisting of core regions in the human reward system may contain receptors for the gender cue. This fundamental, relatively inflexible gender cue then influences and organizes the other male cues—including the visual cues"