Why women's orgasms are on a higher plane

The brain, as any right-thinking person knows, is the most important sex organ. Now doctors think they know why.

The proof comes, in part, from a 44-year-old woman with an unusual medical problem. She would be shopping, doing the housework, or listening to the radio when, doctors from the Western General Hospital in Edinburgh report, "she would suddenly become aware of an internal, ascending feeling indistinguishable from an orgasm".

The orgasms, which lasted up to a minute, were uninvited, unexpected and unwelcome. She had them, on average, once a fortnight for three years. On several occasions they happened when she was driving and she had to pull over and stop until she had calmed down.

Once she was sitting listening to an "emotional" radio play with her sister, when she suffered an episode. On this occasion her left hand started jerking, she collapsed and momentarily blacked out. That was enough to send her to the doctor.

The woman, a divorcee with children, was embarrassed by her symptoms and it took some delicate questioning to eke them out of her. She insisted the orgasms had no definite triggers and were neither pleasurable nor satisfying. The only clue to their cause was a sudden severe headache lasting several days she had suffered two years earlier.

A brain scan revealed a deformed artery in the right temporal pole of her brain. Dr Paul Reading, her neurologist, described it as a type of "vascular birthmark". It had probably ruptured, causing the headache, and the resulting scarring had triggered epilepsy, he said. This in turn led to the orgasms because the area of the brain where the damage occurred is known to be linked with sexual sensations.

Twenty previous cases have been reported of epileptic seizures which triggered the sensation of orgasm, all in women, and all had a structural abnormality in the same area. Dr Reading said: "We know from cases like this where the orgasm centre is in the brain - at least in women."

Only one case is known of orgasmic seizures in a man and the location of the abnormality in that case - in the hypothalamus, the lower- order vegetative part of the brain which controls basic functions such as hormone production - suggests male orgasms have a different genesis.

Could this explain why intelligent mental activity is a more important ingredient of sex for women than for men? Dr Reading was cautious. "It underlines the difference between them," he said.

The woman was prescribed carbamazapine, a drug used for epilepsy, and has led a satisfactorily quieter life since.