Researchers are struggling to understand a rare medical condition where sufferers unknowingly demand, or actually have sex while asleep, New Scientist magazine reported on Wednesday.

Research into sexsomnia- making sexual advances toward another person while asleep- has been hampered as sufferers are so embarrassed by the problem, they not to own up to it, while doctors do not ask about it. As yet, there is no cure for the condition which often leads to difficulties in relationships.

It really bothers me that I cant control it,Lisa Mahoney told the magazine. It scares me because I dont think it has anything to do with the partner. I dont want this foolish condition to hurt us in the long run.

Most researchers view sexsomnia as a variant of sleep walking, where sufferers are stuck between sleep and wakefulness, though sexsomniacs tend to stay in bed rather than get up and walk about.

While sleepwalking affects two to four percent of adults, sexsomnia is not thought to be as common a problem, according to Nik Trajanovi, a researcher at the sleep and alertness clinic at Canadas Toronto Western Hospital.

But an internal survey of sexsomniacs carried out in 2005 that drew 219 reliable respondents concluded that it was more prevalent than medical case reports alone might suggest. Most of the time sleep sex occurs between people who are already partners. Mark Pressman, a sleep specialist at Lankenan Hospital in Wynnewood, Peensylvania., told the New Scientist.

Sometimes they hate it, added Pressman of the reactions of sexsomniacs partners. Sometimes they tolerate it. On rare occasions you have stories of people liking it better than walking sex.

With no cure, addressing triggering factors- stress or sleep deprivation- can help while Michael Mangan, a psychologist at the University of New Hampshire in the U.S. has set up a website, www.sleepsex.org to help sufferers.

Meanwhile Trajanovics devising a procedure for diagnosing sexsomnia in legal cases where sufferers have been accused of sexual assault.