性的興奮
Sexual arousal was also measured in another study, comparing the responses of four groups of people: autogynephilic male cross-dressers, gynandromorphophilic men, heterosexual men, and homosexual men. The penile reactions of the study participants were recorded while watching nine 3-minute film clips (with audio): two neutral (natural scenery with soothing music) and seven showing pairs of individuals engaged in oral and penetrative sex. In these seven, two had cisgender male actors only, two had cisgender female actors only (with fingering as the penetrative sex), and three had transgender women who had breasts and a penis as actors: a trans woman and a man, a trans woman and a cis woman, and a trans woman with another trans woman. Their responses replicated the finding that gynandromorphophilic men are distinct from gay men; the responses of the gynandromorphophiles were not distinguishable from those of the autogynephilic male crossdressers, however. These two groups showed little response to the cisgender male-only stimuli, large response to the cisgender female-only stimuli, but largest response to transgender female stimuli. The responses of the gay men and the heterosexual men both showed the expected patterns of most arousal to cisgender males and females respectively, little to the non-preferred sex, and only some to the trans female actors.