Discrepancies between men and women in reporting number of sexual partners: a summary from four countries.

Men and women in national surveys from four countries, the United States, Canada, Great Britain, and Norway, give mutually inconsistent reports of numbers of opposite-gender sexual partners. In all cases the number of female partners reported by men exceeds the number of male partners reported by women. Gender difference in reporting bias seems to be the most plausible explanation for the discrepancies.