Throughout the course of time, it has proved advantageous for the male to copulate with young and fertile females. Imagery and male sexual arousal. The sexes have been found to contrast with respect to where their fantasies originate from. Due to the sheer scale of this comment community, we are not able to give each post the same level of attention, but we have preserved this area in the interests of open debate. Enhancement of fantasy-induced sexual arousal through training in sexual imagery. Responses to complex erotic stimuli in homosexual and heterosexual men.
US Edition. The incidence of sexual fantasies is nearly universal,  but vary by gender, age, sexual orientation, and society. To measure the reliability of a person's reporting of their fantasies, researchers may compare a person's reported sexual arousal against actual measures of arousal,  using techniques such as vaginal photoplethysmographypenile strain gaugesor other tools, such as genital pulse amplitude, genital blood volumeand heart rate.