It may come as a surprise to many people, but the most desirable length for sex is just 10 minutes, a survey has revealed.
A survey of 50 members of the Society for Sex Therapy and Research, who counsel and treat couples with sexual problems, said that between one and two minutes was too short, three to seven minutes was acceptable, and anything over 13 minutes was too long.
The added that sex lasting between seven and 13 minutes was "desirable".
Contrary to popular fantasy about the need for hours of passionate activity, sex therapists say around ten minutes is perfectly satisfactory.
"Many men and women seem to believe the fantasy of all-night-long intercourse," the Telegraph quoted researcher Eric Corty, an associate professor of psychology at Penn State University, as saying.
"This seems a situation ripe for disappointment and dissatisfaction.
"We hope this survey will dispel fantasies and encourage men and women with realistic data," Corty added.
The findings were published in the Journal of Sexual Medicine.