"Professor Gert Holstege and colleagues asked 13 heterosexual couples aged 19-49 to take part in an experiment. One half of the couple was asked to lie down, with their head inside a scanner, while their partner stimulated them manually to achieve orgasm. To aid the mood, the room lighting was dimmed and all noise distractions shut out. The couples then switched positions and the experiment was repeated. [...] The women were also asked to fake an orgasm so that these scan results could be compared with those taken during genuine orgasms. There were obvious differences. Professor Holstege said: 'Women can imitate orgasm quite well.'" More at the BBC.