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A letter to the editor to New York Times (unpublished) In the recent article in
NYT on The
myth the math and sex, Gina Kolata
takes up the well known fact that men
and women report widely different numbers of sex partners although this is mathematically
impossible. This result is true all
over the world. In our nationally
representative survey conducted in Inspired by Kolata’s
article, we
checked in our data whether the
difference is the same with those who have
few partners and those who have many. It is plausible that those who have had few partners remember
the number of partners better than those
who have had many. But also, those who
have had few partners are in a sense
“losers”; their potential for producing offspring is
lower. Men have a higher pressure than women
to have more sexual partners, according
to evolutionary theory. The number of
partners is directly related to their social
position, for instance. On
the other hand, men and women who have
had many partners are the “winners” and
they have perhaps less pressure to change the
reported numbers from the real ones, at least when they are men. On the other hand they have more
difficulty to remember the precise
number and therefore they might round
the number off in the preferred direction. This is coming out from
the data in
an interesting way. People who have had
fewer than 10 partners have only a
negligible difference between the numbers of partners
reported by men and women. There is no over-
or underreporting. Those who report
having more than 10 partners account for
all the difference: men report having
31.5 partners whereas women report having had
only 19 partners. So big a difference cannot be based only on errors in reporting
One possible hypothesis is that
men and women have a different
definition of what having a sex partner
means (e.g. as in the case of Bill
Clinton), but this is not borne out by the data. The verbal definitions of sexual intercourse given by
men and women in our study were
identical. In fact, the exactly
equal numbers
of sex partners are true for those who have between 10 and 20 partners.
Only
after 20 lifetime sexual partners (15 % of respondents, 30 % are women
and 70 %
men) do the numbers diverge. For those above 20 lifetime sexual
partners, the
difference is very clear: men report 43 partners and women report 30. So the question remains, who is cheating, men or women? Or maybe the assumption that women with
extremely numerous partners (prostitutes) do not participate in surveys
is
true. This latter hypothesis is doubtful, because male respondents do
not
report high numbers of sex with prostitutes. Our hypothesis is that
the men have
no reason to over- report the numbers of their life-time sex partners,
except for occasional rounding off,
whereas women have a very strong interest
in underreporting. They should not be seen as being promiscuous. Thus,
the
number for men having more than 10 partners, i.e. 31 partners, is probably true for women also. We did a further check
controlling
for education, under the assumption that
it is even more important for highly
educated, i.e. more powerful and independent women to under-report (the opposite hypothesis is also
possible: women in a power position have
no need to under- report). The results are somewhat equivocal. The
difference
between men and women is biggest among those who are highly educated
(at least undergraduates).
Women with highest education (university degree) report fewest
partners, but
the women with most partners are those with lower college education,
not those
with lowest education. In the less than 10 partners group the situation
is
completely different: university educated women have the highest number
of
partners and there is no gender difference.
Corresponding to our opposite hypothesis above, they have
no need to
under-report. In any case, it seems
clear that a
relatively small minority of men and women are responsible for the
difference
in misreporting for sex partners and that the number of partners has an
important role here. The hypothesis mentioned by Kolata in the end of
her
article is probably untrue. Sex partners are underreported, not
overreported by
the group of respondents as a whole. Elina
Haavio-Mannila Professor
emerita J P
Roos Professor
University
of Helsinki Back to beginning |