## Sexy Math

Posted on August 23, 2007  Comments (6)

British researchers, stated that men had 12.7 heterosexual partners in their lifetimes and women had 6.5.” These numbers, though Kolata doesn’t say so, are means, not medians. In this case, it’s indeed mathematically impossible that the numbers are correct. The medians in the British sample? Seven and four, same as in the American studyâ€”so you can stop worrying about a transatlantic promiscuity gap.
“It is logically impossible for heterosexual men to have more partners on average than heterosexual women,” she explains. “Those survey results cannot be correct.” Kolata even quotes a theorem to this effect, backed up by mathematician David Gale of Berkeley: The average number of partners has to be the same for men and women.

This article makes several good mathematical and scientific points, including the dangers of trusting reports by participants. Also I can see if this page is more popular than some of the other math posts. For awhile now I have noticed “sex 100” showing up as one of the terms guiding the most visitors to this site. I wondered what that could be – I just took a look: Bdelloid Rotifers Abandoned Sex 100 Million Years Ago. I think maybe those searchers didn’t exactly find what they wanted.

6 Responses to “Sexy Math”

1. MorganLighter
August 25th, 2007 @ 11:12 am

I might be missing something here.
If a male has intercourse with 10 women and each of those women only had sex with him, then wouldn’t the statistics, in this example, be 10 to 1? The converse would be true as well.
Then there is the anomaly that men tend to exaggerate their sexual conquests – to ‘prove’ their manliness while women downplay theirs in order to appear more virtuous.
Lastly, why even bother doing a survey which, in my opinion, is pointless, as most surveys seem to be.

2. curiouscat
August 26th, 2007 @ 9:06 am

The average cannot be off for the whole population: the average can be off for a subset of the population.

On a related topic: Sex in High School – including a map of the population with sexual connections.

3. Curious Cat Science and Engineering Blog » The Science of Kissing
February 11th, 2008 @ 7:19 pm

“It is logically impossible for heterosexual men to have more partners on average than heterosexual women,” she explains. “Those survey results cannot be correct.”

4. CuriousCat: Aztec Math
April 5th, 2008 @ 11:20 am

“By reading Aztec records from the city-state of Tepetlaoztoc, a pair of scientists recently figured out the complicated equations and fractions that officials once used to determine the size of land on which tributes were paid.”

5. Ewan Kennedy
August 14th, 2008 @ 8:56 am

Since the true numbers for the whole population must be equal for men and for women, the inaccuracies must arise either from unreliable statistical sampling techniques (e.g. the group of people questioned does not accurately reflect the whole population) or inaccurate answers given by those surveyed which may be due to dishonesty or inaccurate memories. Denial is a valid survival strategy and it is not uncommon for people to have lied to themselves for so long about unpleasant events in their lives that those events have, for all intents and purposes, ceased ever to have existed. Some pregnant women have even denied ever having had sex. The disastrous consequences for some women of being found to have had indiscreet sexual relationships may go far beyond damaged reputations. They may in some cases lead to the discovery that their children were not fathered by their partners.

6. Jens Hegg
February 20th, 2009 @ 2:30 am

There is the phenomenon of people who do not have sex during their lifetime. Some studies have even shown that there is a surprisingly large subset of people who seem to have no desire for sex. This would tend to skew the overall average would it not if more women or men remained celibate during their lifetime. I’m not suggesting that the results are high enough to skew the results that far. There are not enough monks and nuns out there for that.