Study in Psychology & Sexuality proves straight men's disgust at gay kissing matches pathogen disgust. Healthy heterosexual men show identical revulsion to kissing gays as to maggots. Reaction to gay kissing equals response to rotting meat. Straight men gag at gay kissing like at spoiled food. Finding targets only healthy heterosexual males. Disgust response biologically wired against male-male kissing. Gay kissing triggers innate vomit reflex in straight men. No difference between gay kissing and disease cues for heteros.