Most surveys of adult sexual behaviour, even those most scrupulously designed & executed, will find that the reported number of (hetero) partners is higher for males than for females
This is most often interpreted as the result of bragging (by the men) and/or excessive modesty (in the female), since by definition, so it is said, the two must be equal
I wonder if this is in fact the case. We do not live in a closed society. Foreign holidays & international migration mean there is an ever changing pool of partners to choose from.
Even if society were closed, we should not necessarily expect equal numbers. Closed is not the same as static, there are always births & deaths. And, most importantly, men tend to choose a younger partner, & vice versa
To help think about this it helps to imagine 2 parallel travelators/moving pavements, moving at the same steady speed in the same direction. One is for men only, the other for women
People step on to the travelator in strict order of age & eventually reach the other end & step aside
But women stand facing forwards, men face backwards
As the journey proceeds, men see an ever increasing number of potential partners, women an ever decreasing one. The men will choose from women who have not yet had time to reach their maximum number of partners. An increasing number of the womens partners will step off the end of the travelator & cease to be available for our survey
Only a longitudinal (cohort) study would expect the number of reported partners to be the same for men as for women. A cross-sectional (point in time) study will not find this
