Friday, 14 August 2015


Evan Davis has caused a big hoohah by suggesting that gay men are more promiscuous than straight people.
This sounds like the kind of question we can answer with statistics! Now obviously the statement could be interpreted in different ways, but I've chosen to look at number of sexual partners. Simply looking at the amount of sex various people have is probably inadequate, since most sex presumably happens within relationships, which really isn't what he was talking about. Looking at how casual the sex people have might be worthwhile, but this is a trickier thing to get data on. 

Okcupid tried to answer the question this using their self report data, but this seems inadequate to me. Since you're making a public profile explicitly looking for a date, your answers are about as influenced by social desirability bias as is possible to imagine, as shown elsewhere on their own blog. The Daily Mirror also had a go last year, and got as far as finding out one paper exists, but couldn't be bothered doing it properly, since journalism is pretty hard.

Notes on the data I do have.
  • Natsal is the UK national sexual attitudes survey, it's pretty massive.
  • There are lots of other papers out there covering similar ground, but the ways they present the data is often not directly comparable, and often grouped together at the high end, when we really want medians and means for gay and straight men from the same survey, which we can get from the natsal.
  • For those of you unfamiliar with the terms, mean is the total number of sex partners divided by the number of people, while median is the number of sex partners where half the sample have had more and half the sample have had less. The mean is much higher in all cases here because the data is skewed, a small number of men have a LOT of sex, and this is reflected in the mean but not the median. It's therefore important to report both.
  • Natsal-3 is the most recent, but I can't find the exact data we want for gay men from that, so have gone back a decade to an earlier version to keep the comparisons valid. 
  • In order to get directly comparable data I've had to go for partners in the past five years, rather than lifetime. This shouldn't really make much difference, but the often claimed average of 6 is the median of straight lifetime partners from this dataset.
  • The term 'men who have sex with men' rather than gay is used in an attempt to keep things objective and avoid tricky issues around identity etc.
  • Women typically report fewer partners than men, so it is likely straight men are exaggerating the number of sexual partners they have had, or at least using slightly different definitions of what sex is, in spite of the researchers specifying oral, anal or vaginal intercourse. I've focused on figures for straight men but there are some for women in the linked papers if you're interested.
  • Results aren't broken down by age for MSM, so I'm comparing to all, but the mean age of the two samples is very similar (31.5 for MSM, 31 for non-MSM).
  •  I haven't looked into lesbian sex because I don't know what lesbians do.

Anyway, this is what we get -

Straight men over past 5 years - Mean 3.8 Median 1

MSM over past five years - Mean 24.1 Median 4

We also have this, which is analysing the same dataset, though comes out with slightly different numbers, I'm not sure why, but they're not massively different.

"Men with a homosexual partner during the past 5 years reported a mean (SD) of 26.7 (109.9) sex partners during that time, compared with 4.1 (8.3) among those men who reported having no homosexual partnerships."

The standout problem here, some of you may have noticed, is that because the 'gay' group are defined as men who have sex with men, there are none in that group who are celibate. This obviously skews our results a little. My cack-handed correction for this by excluding all straight men who haven't had sex in the last five years pushes their median up to 2 and the mean up to 4.2. This assumes the number of celibates is similar in both gay and straight men, which probably isn't a reasonable assumption, but I doubt it's incredibly far out and we'd need a huge number of celibate gays in order for this to affect the conclusion. We can pretty safely say that out of those that do have sex, gay men have more sex partners than straight men, and that Evan Davis is pretty right. It might be cruel to generalise, and assuming every gay man has tons and tons of sex with different guys is silly, but there is a notable difference in behaviour on average.

In addition, there does seem to be a far higher rate of nonmonogamy among gay men than among the population as a whole. General estimates of the number of open relationships are tricky to find, but seem to hover around 4% of couples generally while among gay men the number may be as high as around half.

The question, then, is why. Testosterone is associated with a higher sex drive in both men and women, and this must be a large part of the explanation of why men have a higher sex drive than women. Gay men don't seem to have much difference in testosterone levels though, so my guess would be that the higher number of sex partners is probably a result of gay relationships being men squared, rather than anything particular about gay men themselves. It's plausible that tinder as a social technology has allowed some straight men to reveal their preferences to act in a similar way, but I'm generally sceptical of most claims about the rise of hookup culture, and await data from the last couple of years in particular with interest.

As usual, All Stereotypes Are Correct.