What's Your Number?

According to the premise of the recent Anna Faris movie by that title, once a woman has had in excess of 20 sexual partners, her chances of ultimately getting married drop precipitously and she falls socially into the dreaded categry of "slut."  This rom-com, or sexy comedy has its faults, but it also raises some occasions for thought.


First of all, what is the mean number of sex partners a woman is likely to have over an extended period?  Typically, fewer than the number a man is likely to have.  One source put it at four; while the typical number for men is seven.  However, in the case of both sexes the mean number of sex partners is likely to be in the form of a skewed right distribution; like below, with the number of sex partners on the horizontal (X) axis and the frequency of cases on the vertical (Y) axis:

In other words, a small number of people of either gender account for having unusually large numbers of sexual partners.

If we stipulate that women who have more than 20 sexual partners over an extended career are less likely to marry, why is that the case?  I offer several reasons:

1.  She's looking for love in all the wrong places.  Specifically, finding guys who are interested in a only in a short-term liasion (cads).

2.  She might be using the wrong criteria in finding mates: ignoring some who are sleepers who might be more stable and good quality husband in preference to those merely with one kind of skill.

3.  Her judgment might be impaired due to alcohol, drugs, or stupidity.  Or some combination of these.

4.  She may have certain traits (physical, behavioral, or character) that preclude her being in any permanent relationship.  In other words, by "being easy" she does get to go out.

5.  Finally, she may be a short-term player also.

But there is a fundamental flaw in the assumption:  namely, that you can precisely define 'slut.'  Well, it does use an operational criterion, so it does meet one scientific criterion.  Just as a curiosity, you can Ride the SLUT in Seattle without shame or blame.  SLUT is a local acronym from South Lake Union Transit.