Don't think that what you see in a porn movie is what will make your partner happy. But we must admit that many (especially) young men believe that great sex means sustaining sexual activity with their partner for at least one hour, when they have long passed the sense of boredom of what they're doing.

But a new research published in the "Journal of Sexual Medicine" comes to shatter these unrealistic beliefs of what healthy sex means. Of course, not the premature ejaculation is the solution, but 7 to 13 minutes is the ideal, and even three-minute sex is "adequate."

The research focusing on the ideal length of time of penetrative sex was made on a random sample of American and Canadian subjects. People rated 7 to 13 minutes most "desirable", but intercourse of 3 to 7 minutes was regarded as "adequate", while anything less was "too short" and over 13 minutes was "too long".

American researches showed that people expected penetrative sex to last 15 to 20 minutes, but less than 50% of the men were found to perform longer.

"This was a situation ripe for disappointment and dissatisfaction. In the fantasy model of male sexuality, men have large penises, rock-hard erections, and can sustain sexual activity all night long," said lead researcher Dr. Eric Corty, from the Behrend College in Erie, Pennsylvania.

"It appears that many men and women hold this fantasy. The results from the present study, by providing a realistic not a fantasy model of sexuality, are useful both in treating people with sexual concerns and dysfunctions, and, with wider circulation, in preventing the onset of sexual dysfunctions," added Corty.

"There is a major gender difference in this area. Usually women are quite happy with short intercourse, and are not bothered about prolonging it at all, but nearly all men want it to be much, much longer. It is important not to obsess over the length of intercourse, with time often suspended during the act anyway," Dr. Jane Howard, a Brisbane-based medical sex therapist, told The Australian.