London - When men are asked how many women they have slept with, they notoriously pick a high number.
But aspiring Casanovas who report twice as many sexual partners as women are not in fact just exaggerating.
A study has found men probably do not realise when the number they give is too high. It is simply that they are more likely to estimate the number of women they have bedded, while women tend to have remembered each partner.
The National Survey of Sexual Attitudes and Lifestyles, carried out in Britain every decade, shows men report an average of 14 sexual partners over their lifetime, while women say they have slept with just seven.
Researchers looked at more than 15 000 responses in the survey, with men indicating they were more likely to say they guessed or estimated the number, or remembered some partners and estimated the rest. Women, however, answered much more often that they "just knew" the number or "remembered each partner".
The study led by the University of Glasgow found that men guess and women count their partners, with females more embarrassed by one night stands and casual sex, which may lead them to reduce their numbers. Women felt worse about one night stands, with only 9.3 percent saying they were "not wrong at all" compared to 17.5 percent of men
Dr Kirstin Mitchell, who led the research from the Institute of Health and Wellbeing, said: "Most of the difference between men and women is in the way men and women count up their partners, a greater tendency for some men to report very high numbers of partners and differences between men and women in attitudes to casual sex."
The Sexual Attitudes and Lifestyles survey of people aged from 16 to 74 showed the gap in men and women’s numbers of sexual partners may be down to their attitudes.
The study, in the Journal of Sex Research, found counting and attitudes towards sex explained two-thirds of the "gender gap" in numbers of conquests.
Responding to the research, Denise Knowles, counsellor and sex therapist at relationship charity Relate, said: "Men may feel under pressure to impress their friends and therefore guesstimate their number as being higher.
"Women are often misjudged if they’ve had a 'higher than average' number of sexual partners, which can lead to feelings of guilt and shame.
"These findings highlight a real need for robust relationships and sex education in schools."