My theory is its a pheromone reaction. Trans women typically have higher levels of estrogen than cis women (at least if they're doing monotherapy). I've noticed that I tend to experience a sort of intoxication around women with high estrogen (for example around ovulation) and can actually tell if cis women are pregnant before they are showing because its so reliable. I know humans aren't supposed to be able to communicate by pheromones but I can't think of any other reasonable explanation. So yeah if someone walks in rocking 300,pg/ml, they'll have my undivided attention.