Women seem to be evasive when they are asked about their partners, researchers have found.
Half lie because they 'feel ashamed' of the number, while a further 19 per cent don't want to be seen as promiscuous.
A fifth of women would be dishonest about their number of sexual partners if their new partner had slept with fewer people than them.
Researchers have also shown that there is a split between the genders when it comes to answering the potentially embarrassing question.
A higher proportion of men- 43 per cent - lie to their new partner. In these cases, around 60 per cent increase the amount.
Around 42 per cent of men said they were 'reluctant' to settle down.
In contrast, 21 per cent of the women claim to be 'reluctant' to settle down in a relationship.
The average number of sexual partners - according to the survey by www.MyVoucher-Codes.co.uk - was seven for women and 13 for men.
"I would suggest starting a new relationship with honesty .If you start with a lie, it is more likely to end with a lot more lies," the Daily Mail quoted Mark Pearson, managing director of the website as saying.