Crusade, Denial, or Concerned Tolerance?: The Case of MSM and HIV By Bryan Caplan

Briggs and Tabarrok provide strong evidence that gun ownership increases suicide risk. The response to their research provides strong evidence that readers swiftly twist research to suit their prejudices. A slight caricature of the two standard reactions:

Reaction #1: Crusade. Guns cause suicides, suicides are bad, so guns must be banned. Anyone who disagrees is anti-science.

Reaction #2: Denial. Guns mustn’t be banned, so either guns don’t cause suicides, or suicides aren’t bad.

The wise reaction, though, is what I call Concerned Tolerance.

Reaction #3: Concerned Tolerance. Guns cause suicides, and suicides are bad. But despite this risk, guns also have major upsides. Self-defense aside, shooting and hunting are two popular American hobbies. It’s far from clear that the suicide risk outweighs these benefits. But perhaps gun-owners underestimate this risk. So let’s politely publicize the Briggs-Tabarrok findings, then let individuals make their own choice. In many cases, informed individuals will take extra precautions (e.g. locking up their guns) rather than actual quitting their risky behavior.

Concerned Tolerance may seem like mere libertarian dogma, but the truth is that most non-libertarians rely on Concerned Tolerance most of the time – even for choices that are vastly riskier than gun ownership.

Like what? Consider male-on-male sex. It clearly raises your probability of dying from HIV. By how much? This impressive study by Susan Cochran and Vickie Mays (American Journal of Public Health, 2011) estimates the probability that men who have sex with men (MSM) will die of HIV-related causes. Since it is based on past deaths, it is quite possible that the risk has changed. But it’s the best piece I could find on the topic, and you’ve got to start somewhere.

The sample:

We used data from a retrospective cohort of 5574 men aged 17 to 59

years, first interviewed in the National Health and Nutrition

Examination Survey III (NHANES III; 1988-1994) and then followed for

mortality status up to 18 years later. We classified men into 3 groups:

those reporting (1) any same-sex sexual partners (men who have sex with

men [MSM]; n = 85), (2) only female sexual partners (n = 5292), and (3)

no sexual partners (n = 197). Groups were then compared for all-cause

mortality, HIV-related mortality, suicide-related mortality, and

non-HIV-related mortality.

The risk estimate:

Compared with heterosexual men, MSM evidenced greater all-cause

mortality. Approximately 13% of MSM died from HIV-related causes

compared with 0.1% of men reporting only female partners. However,

mortality risk from non-HIV-related causes, including suicide, was not

elevated among MSM.

Of course, some MSM would have died of other causes during the sample period even if they never contracted HIV. But very few. If you assume that HIV-positive men would have died of other causes at the normal rate (6.6%), this still means that being an MSM raises your probability of HIV-related death by 12 percentage-points.

Converting that figure into an annual estimate (12 extra percentage points over 18 years) implies a .63 percentage-point increase in the annual risk of death by HIV. That is an staggering risk. By way of comparison, Briggs and Tabarrok found that People Living in Households with Guns (PLHG) had .01 percentage-point increase in their annual risk of death by suicide. Thus, the risk of dying of HIV because you’re an MSM is about 60 times greater than the risk of dying of suicide because you’re a PLHG. If another research design found that Cochran-Mays overestimated by a factor of ten, the Cochran-Mays effect would still be over six times as large as the Briggs-Tabarrok

effect.

How should we react to Cochran-Mays’ risk estimate? As usual, we’ve got three basic options: Crusade, Denial, or Concerned Tolerance.

Reaction #1: Crusade. Male-on-male sex is very dangerous, so let’s pass and enforce draconian laws against it. Anyone who disagrees is anti-science.

Reaction #2: Denial. Male-on-male sex isn’t dangerous. Cochran-Mays must be incompetent and/or liars. Or maybe male-on-male sex is dangerous, but people wouldn’t engage in it unless the benefits outweighed the costs, so there’s no need to study or publicize the risk.

Reaction #3: Concerned Tolerance. Male-on-male sex is very dangerous, and people could easily underestimate its risks. But despite this risk, male-on-male sex has major upsides. Some guys really love it; some would feel spiritually incomplete if they quit. So despite the massive risk of being an MSM, it’s

far from clear that this risk outweighs these benefits. But

perhaps MSM underestimate the riskiness of their behavior. So let’s politely publicize

the Cochran-Mays findings, then let individuals make their own

choice. In many cases, informed individuals will take extra precautions

(e.g. having fewer sexual partners) rather

than actual quitting their risky behavior.

As far as I can tell, the vast majority of modern Americans take a Concerned Tolerance approach to MSM. If they’re right to do so here, why not across the board?

P.S. Please don’t protest that “Sexual orientation is not a choice.” I’m talking about sexual behavior, not orientation.