Let's be honest. Did any of us really believe that old chestnut that men think about sex every six seconds? After all, that would mean the average chap having up to 10,000 racy thoughts a day. Which would barely leave him time to dim the lights, put on some romantic music and snuggle up, let alone anything else.
Nevertheless, scientists have decided to put the six-second theory to the test.
Their extensive research has found that men do think about sex rather a lot.
But it's more in the region of every 50 minutes, or a less frenetic 19 times a day. Women, too, let their minds wander to matters risque. But they only manage an average of ten thoughts a day.
The researchers worked out how many times men and women thought about sex by giving them a 'clicker' machine to press when they had any such thoughts.
They were also told to click every time they thought about eating or sleeping.
And while women's minds did turn to sex ten times a day, they spent much more time thinking about food.
They had an average of 15 thoughts a day relating to hunger pangs, the desire to snack or even anticipating what they were having for lunch. While men also thought about food, sex remained the biggest preoccupation.
The scientists had asked both men and women to include memories and fantasies when noting their sexual thoughts. And although the average male total was 19 a day, there was wild variation, from as little as one a day to a rather imaginative fellow who registered 388 sexual thoughts or one every two-and-a-half minutes.
The most any woman thought about sex was 140 times a day, or just under once every seven minutes, according to the study which will be published in the Journal of Sex Research next month. The lowest was once a day.
Psychology professor Terri Fisher, who led the study, says the variation in figures shows frequency of sexual thoughts is related to a number of factors other than gender.
"It's amazing the way people will spout off these fake statistics that men think about sex nearly constantly and so much more often than women do," she says.
"When a man hears a statement like that, he might think there's something wrong with him because he's not spending that much time thinking about sexuality.
"But there's really no good reason that our society should have believed that men are thinking so much more about sex than women."
The 163 women and 120 men surveyed were all students at Ohio State University and aged between 18 and 25.
The researchers found the men also thought more about food and sleep than women.
Eating entered their heads 18 times a day on average and sleep 11 times. For women, eating cropped up 15 times a day, and sleep just 8.5 times. Professor Fisher says this shows men are more focused on their "biological needs".
- THE DAILY MAIL