A Natural History of the Fag Hag?

Irresponsible Thoughts on Genes, Germs, and the Science of Homosexuality

They say a little knowledge is a dangerous thing.  I say a little evolutionary psychology is the fucking devil. 

As sentient critters, we are at once blessed and cursed with a natural cognitive predisposition to recognize and seek out patterns, to discern order in virtually every detail of the complex and noisy social matrix in which we are contained. Of course, pattern recognition can be a good thing when it helps us detect cheating or predict crop cycles or figure out who wrote the Unabomber Manifesto. But the same neuro-mechanical biases that help us make sense of the world also help us make sense of nonsense. This is why people waste time obsessing over Virgin Mary Pop-Tarts or plotting out signs of Masonic cryptocracy in every frame and grain of the Zapruder assassination footage. 

Once you tune in to the Darwinian gestalt, the pattern-decoding program has a way of kicking into a kind of quasi-paranoid overdrive. Like an aging hippie who sees bong potential in fire hydrants, you begin to sniff around for the adaptive significance of damn near everything. Even if you can shake off Desmond Morris’s salacious riffs on tits and ass, the cues still lurk in every tick and quirk, begging for some retrofitted just-so EP narrative to satisfy that hard-wired itch for tidy explanation.

Why do people yawn?

What’s with the southpaw?

How did people get to be so smart? Or so stupid?

And why are all the chicks in the office ragging at the same time?

The questions are endless.  And some of them invite trouble.  If you’re not careful, you may find yourself on the trail of aquatic apes. Or, if you really want to stir at the sociopolitical fringe, you can study up on those incendiary  narratives about "hostile ethnic nepotism" as expressed as the “culture of critique.”  Some of you will know what I'm talking about.

It's probably better, however, to play it safe and bide your time mulling over mystery of the female orgasm. At least the research can be interesting.

But if you’re looking for a special kind of trouble, you can apply your imaginative skills toward solving one of the more elusive and intriguing puzzles in the scrapheap, which concerns how to cook up a plausible evolutionary account of male homosexuality.

Lesbianism is easy enough since the iron law of patriarchy pretty much guarantees that women are going to be fucked – literally and figuratively – across time and cultures, regardless of their penchant for rug munching and dog shows.  But the gay thing is different. Buggery and blow jobs may make for good church camp recreation, but an exclusive male preference for bungholes and boyflesh is maddeningly difficult to reconcile with the rudiments of genetic math. If a behavioral trait has a genetic basis, Darwinian logic tells us it must have conferred some adaptive advantage. But the only way to get from there to here is through natural selection, which for our species, usually requires sex. Procreative sex.  From an evolutionary perspective, men fucking men would seem to make about as much sense as tree humping.

Not that there’s anything wrong with that.

Apart from the tendrils of scientific contention, to which we will turn, your initial foray into this very special controversy is sure to expose you to a curious -- if superficial -- inversion of the politics of nature and nurture. While speculation about genetic origins remains anathematized with respect to matters of race and sex differences,  you will discover that once the topic turns to sexual orientation, the strictures of PC decorum about face to favor the default position that we are indeed “born that way.” The double standard is, of course, entirely political; if gayness is an inborn trait, then the arguments marshaled by those who would frame and stigmatize it is a moral choice are pretty much dead on arrival. The seldom mentioned irony is that while the evidence is pretty robust with respect to the biology of sex and even race differences, the evidence for genetic gayness remains much more speculative, and the bio-etiological conjectures that have been floated thus far are exceedingly more difficult to assess and explain.

What’s more puzzling is that while the goodly majority of ostensibly open minded people seem perfectly at ease with the idea of innate homosexuality, the same people tend to show an insipid lack of curiosity as to how such a genetically peculiar predisposition could evolve and survive in the soup of civilization. Yet if gayness is in the genes – and I think there’s a decent chance it is – it must have somehow provided a fitness advantage. The question few people care or dare ask, is how?

As it turns out, there are all kinds of ideas.  Some of them are plausible enough, others are highly improbable. And others are downright silly.

The one you hear the most about was hatched by the preeminent sociobiologist, E.O. Wilson, who speculated that gay genes might have provided a group-adaptive advantage manifest in extended families where gay uncles, by dint of their presumably extra-avuncular social skills, were imagined to have groomed their siblings to produce more nieces and nephews, thus ensuring a side-door method for gay genes to descend. Wilson’s theory is propped up by an adaptationist model known as “inclusive fitness,” whereby extended kin selection provides the mechanism for genetic dynasties to pass down without direct appeal to the messy business of sexual reproduction. Inclusive fitness models have proven valuable in explaining a number of once-puzzling altruistic behaviors in bugs and other non-human animals, and they probably go a long way toward making sense of nepotism and even ethic nationalism among us sapient bi-peds. But while the “good uncle” nostrum remains a fun subject for parlor chat and idle speculation, it is pretty well demolished by a cursory review of the genetic math.

Writing for The Atlantic in 1999, science journalist Judith Hooper dispatched Wilson’s theory with a clear-cut empirical reality check:

To counteract a whopping fitness cost of around 80 percent, gay men would have to be very, very good uncles indeed -- especially given that they share with nephews and nieces only 25 percent of their genes. Simple calculations show us that in order to compensate for not reproducing, a gay uncle's investment in a sibling's children would have to be twice as strong as a parent's. If this were the case, it could not have escaped our attention.

In the wake of Wilson's interesting false start, most thinking has eschewed kin selection in favor of various theories of frequency-dependent balance polymorphism where the evolutionary scenarios are less difficult to reconcile with stability differentials.  Some such ideas are well-summarized in Jim McKnight's invaluable book, Straight Science?, which is still worth reading. 

McKnight’s own theory is one of my favorites. He argues that male homosexuality is a heterozygously regulated phenomenon, with the gay genes being carried by straight and gay men in dose-dependent frequencies.  Assuming the primary role of female-driven sexual selection in human affairs, McKnight imagines a marginal group of females rejecting classically defined optimal mate-types, i.e, those brutish, boorish, athletic fuckers who are a head taller than The Hog, in favor of gents who exhibit traits such as charm, intelligence, and empathy, which may signify good breeding and nurturing potential, at least at the peripheral bounds of the dating game. “Homosexually-enabled heterosexuals,” in McKnight’s parlance, might thus be attractive enough mates to sustain the genetic lineage for men carrying the stronger, i.e. determinative, dose of the gay heterotic constitution to tag along.

McKnight’s idea -- which, I should mention, parallels in many respects with economist Edward Miller's work on "portfolio diversity" in evolutionary sex economy --  has a goldilocks quality in that the operative sexual selection exercised by females in their mate choice would have diminishing returns in proportion to the infusion of homosexual genetic loading in a population:

Women are attracted to men who carry gay genes because they admire the benefits these men gain from carrying them. Even so, they are suspicious of, and will reject, any man who has homosexual tendencies as this may reduce the genetic fitness of their potential offspring

“Men who have a ‘measure of gayness,’” according to McKnight, will thus “enjoy a reproductive advantage relative to their homozygous [i.e., exclusively homosexual] peers.” By exhibiting a behavioral portfolio that features attractive signals, homosexually enabled straight men may be the porridge that goldilocks chose: “just right” to ensure the penetrance of otherwise reproductively deleterious gay genes over time, but only at a marginal equilibrium.

The elegant thing about McKnight’s theory is that explains why expressed homosexuality would only be found at certain marginal levels in a population; a “frequency-dependent balance” guarantees that too much genetic homosexuality will be selected against, while the heterozygous carriers will carry the torch, so to speak, insofar as they remain conspicuous as charming, and perhaps caddish, mate choices.

The problem with McKnight's theory, and with other notions centered around models of balance-polymorphism,  is that while they do a pretty good job of explaining how homosexual genes might be sustained in a population, they fail to adequately account for how exclusive gayness got started in the first place.  Even if dandies and cads can secure a marginal sexually-selected niche with their epicurean charm and seductive wiles, why would the tail end of this strategy come to be expressed as a positive preference for cocksucking? 

Again, there are theories. Some speculate that it may have initially resulted as an offshoot of enhanced sex drive. Or it could be under social conditions that prevailed in the past, preferential homosexuality was sufficiently stigmatized (or bisexually expressed) so that the fitness costs didn't matter so much.  Even Oscar Wilde had a litter. 

And I have my own little idea, which is so crazy it’s almost certain to be wrong. Let me bore you with it anyway.

I am wondering if male homosexuality could have evolved as an adaptive strategy whereby some members of preliterate hunter-gatherer societies secured personal protection by acting as female sexual surrogates. This might have been particularly useful on long hunts, expeditions, or military adventures during which an all male band of brothers would be cut off from sexual opportunities involving village-bound females.  Assuming it doesn't collide with some well established anthropological truism or some fundamental principle of population genetics of which I remain blissfully ignorant, I think such a hypothesis (which we might call “adaptive female surrogacy”) would have the advantage of being individual-adaptive – with a group-adaptive benefits – and it would fit nicely with a whole slew of gay stereotypes.

The basic idea is that in addition to safeguarding their own survival (and long term reproductive opportunities) through risk avoidance (the indi-adaptive hook), a “tribal female sex surrogate” would also serve a social utilitarian function (the group-adaptive corollary) inasmuch as his sexual availability could mitigate against the sort of internal conflict and infighting that would be exacerbated by pent-up sexual aggression. This would mean that tribes securing such a role among their ranks would gain greater group cohesion and consequently have an adaptive advantage over other male-composed expeditions lacking the same outlet for reckoning group conflict and managing the psychological detriments arising from long term abstinence.   

To present a presumptive scenario as a crude EP narrative, we might imagine a clan of cave-guys leaving the kidlings and womenfolk to tend the home turf while they venture abroad in quest of big game or fire or vengeance or whatever.   Our roving cro-mags, it seems safe to assume, would be destined to encounter all manner of dangerous contingencies in their journeys, and bragging rights (as well as procreative opportunities) would naturally belong to the guys who take greater risks in the face of such peril.  But bravery is costly business, and many of our most intrepid tribesmen will surely meet their fates while attempting to spear saber-tooths or test the quicksand or whatever.  Such are the breaks.

But let's imagine that among the group there's one young, low-ranking cave guy who's smart enough to know he doesn't stand a chance of making it in the hierarchical scheme of things.  We'll call him "Andrew."  Now let's say the day comes when it's Andrew's turn to prove his mettle by leading the group in some potentially deadly situation or another, only instead of accepting his assigned risk-taking duty, Andrew decides he'll have a go at bargaining his way out of the situation.  Having long observed the other guys to grumble over how they long for the sexual favors of the fair cro-magnonettes back home, Andrew decides to play his best hand.

"Listen guys," he ventures, "as much as I want to help out, I'd really rather not be the first one to taste these mushrooms. But if anyone wants to indulge in my place, I suppose I could offer, maybe, um...a blowjob?"   

Andrew's gambit might turn out a number of ways, but assuming just one of his high-ranking fellows is horny and good-humored enough to take him up on his proposal, well, our guy just may have secured himself a new and novel sinecure within the group. Andrew, we might then appoint as the first "tribal female sex surrogate".  Sure, he's not like the cave-chicks back home, but the guys generally agree that he provides a nice diversion when you're bound-up and bored with self abuse.  Besides, with Andrew around to relieve the tension, it seems things aren't so tense on the road anymore. The guys are more focused on the hunt and less prone to club each other to death.  Come to think of it, four out of five tribe guys agree, the expeditions aren't nearly so dreadful these days, what with the new kid on BJ detail.  He's a good mascot, that Andrew. Maybe we'll keep him around.

With Andrew's newfound role proving advantageous for the group as well as for his own immediate survival interests, it seems it would stand a chance of becoming a secured -- if unofficial -- status within the social order.  Natural selection would then do its thing, ensuring that future "hunting mascots" would be ever more fit to the task.  This would seem sufficient to make a homosexual evolutionary strategy plausible, if not a matter of practical inevitability.                                  

That increasingly homosexually oriented group members gravitating to the surrogate role might be less likely to reproduce than other group members may not be as problematic as it first seems if the genetic math based on present trends did not apply under past conditions. Moreover, considering the long term survival advantage conferred by their risk-evasive social status (in a risk-pervasive environment where longevity is rare), the reproductive success scales might have once been tipped in the sex surrogate’s favor by virtue of his having a greater lifetime of reproductive sexual opportunities, to say nothing of the greater proximity to females he might come to enjoy given his uniquely trusted status as “one of the girls.” 

Such an angle might be especially plausible under polygamous social structures, where most men are cut off from reproductive opportunities altogether. By securing feminine social roles, the inconspicuous -- if infrequent -- sexual access to the harem enjoyed by effeminate males might suffice to tip the evolutionary scales.  Just enough.   

Even if sex surrogates only rarely had reproductive intercourse, maybe it could still have once been sufficient to guarantee enough of a genetic dynasty to kick things off. On this point it's worth noting that even today most gay men have sex with women at some point in their lives, and many of them have kids. The question is how much more frequent would gay male procreative success have had to have been in the past (and how distant that past) to provide a basis for  gay genes to enter the population?          

Under a social order where sex surrogates are ascribed a valued status, it would also make sense that effeminate traits would be selected for, since such traits would stand in rough mimicry of the absent female and signify the sexual surrogate's role within the group.  The most remarkable mimicking strategies abound in nature, so why not in a novel cultural mode?

Again, having not thought rigorously about this and readily admitting my ignorance regarding the relevant anthropology, sociology, sexology, and genetics, it does seem that many of the most salient contemporary observations (and stereotypes) about male homosexuality fit rather well with a socio-cultural-evolutionary scenario thus imagined.  Here follow a few:

• Female surrogacy would help to explain why the majority of gays  (and for the sake of argument we might speculate the vast majority of "genetic" gays) are self-described "bottoms," since the classically submissive/female sexual temperament would make for a more popular female-surrogate.
• Female surrogacy would shed light on the strong aesthetic preference for hyper-masculine traits -- with military and athletic fetishism being ever prominent in the relevant iconography -- that prevails in gay culture.  If the selective advantage of being gay in a preliterate hunter-gatherer society is to afford the female-surrogate protection from physical danger then it makes sense that his selective preference would favor the most able warriors, since currying sexual favor among the Alpha would be the best possible survival strategy.
• Female surrogacy would  comport with gay mate selection, such as it is, being less status-oriented when compared with that of women. Females have a sociobiological interest in securing a mate who will be a long-term provider with a vested interest in his genetic offspring (thus social status cues assume greater importance, and sexual selectivity is favored over promiscuity); gays-as-female-surrogates, on the other hand, would have a survival (and indirectly sociobiological) interest in securing short term protection from the entire male out-group, and would stand to benefit most by winning favor among the most physically able men (thus his preferential emphasis would tend to favor physical prowess over other status cues, and the sexual strategy would emphasize promiscuity over selectivity).
• Female surrogacy would be consistent with the stereotype that gays are smart, since the success of a novel within-group evolutionary strategy is perforce evidence of adaptive ingenuity.
• Female surrogacy would be consistent with the stereotype that gays display superior interpersonal skills or social intelligence. In addition to making for a more convincing (and hence adaptive) proxy for female traits, the ability to interpret psychosocial cues would be crucial to the success of any survival strategy where the management of sexual politics is at issue.
• Female surrogacy would be consistent with the stereotype that gays are averse to participation in sports and military affairs.  If the evolutionary strategy was to preserve a genetic legacy by avoiding the front lines, then it would follow that genetic descendents would show less inclination to participate in contemporary events that emulate or entail aggressive conflict.
• Female surrogates might have been the more easily groomed for "intercrural" sexual favors notoriously enjoyed by those pederasts of Greek antiquity, among others. 
• Female surrogacy would be consistent with the relative lack of sexual jealousy expressed by gay men in comparison with heterosexuals.  If jealousy is linked to a broader sociobiological drive to preserve one’s genetic legacy, then it wouldn’t really fit with the sex surrogate’s particular in-group strategy.   

But like I said, it's easy to get carried away with this shit.

Besides, at this point, I imagine you've probably  thought of any number of problems  with such a scenario.  I've thought of a few myself.  For one thing, there appears to be scant evidence that homosexuality even exists in most contemporary hunter-gatherer societies. As Gregory Cochran has pointed out, modern primitive cultures typically express incredulity when they are informed of the existence of man-on-man action.  "If you look out in the real sticks," he notes, "say among the Kalahari Bushmen, there doesn't seem to be any [preferential homosexuality] at all.   Typically,   hunter-gatherers have trouble believing that homosexuality actually exists."  And as  Steve Sailer patiently pointed out when I suggested this idea for his consideration, "if male homosexuals were physically more feminine than male heterosexuals, I might buy this proposed evolutionary mechanism, but they're not."

Still, there are some curious strands that might invite deeper consideration of my probably wrong pet theory.  For example, University of Delaware psychologist Linda Gottfredson has emphasized the role of accidental death in directing brain evolution with special reference to general intelligence. In her monograph, "Innovation, Fatal Accidents, and the Evolution of General Intelligence," she draws insight from the emergent field of cognitive epidemiology to make her case. "The prevalence, etiology, and demographic patterning of accidental deaths in both mordern and hunter-gatherer societies," she argues, "provide clues as to how these could have winnowed away a group's less intelligent members through human evolution"

...fatal accidents kill a disproportionate number of reproductive age males, their accidents are generally associated with provisioning activities, and preventing these is a cognitively demanding process. 

So maybe it's not too much of a stretch to speculate about the longevity gains that might confer from a truly novel strategy for risk avoision.  And there is some evidence that gay men have pronounced mental abilities, with a cognitive structure favoring verbal over visual-spatial skills. Which would fit, as far as it goes.

The thing is, it only had to happen once. And it didn't have to happen the way I imagine it. If a gay gene could gain admission to the stakes through such or similar means, it seems reasonable to imagine that in the slow process of being admixed out of the broader equation, the heterosexually modified constellation of temperamental traits that might remain among the carriers of residual female-surrogate genes could present in just the sort of personality that would find female favor in McKnight's balance-dependent scenario.

But I fear I've gotten a bit derailed with all this far-flung speculation.  So before waxing Kiplingesque about the evolutionary  basis for male homosexuality, it might be a good idea to firm up the evidence that there really is a genetic explanandum to beg such an overarching theory. 

I mean, they have discovered a "gay gene," haven't  they?

The short answer, as it turns out, is: maybe.  The long answer is: probably not.  The qualified long answer: not yet, anyway.

A few years ago, you will recall there being a lot of fast and loose media chatter about the the whole business.  The most vocal and prolific proponent of the purported discovery was a geneticist named Dean Hamer, a solid guy who still plugs away for the National Institute of Health and who happens to be gay. In several papers and in his book, The Science of Desire, Hamer professed to have identified "a correlation between homosexual orientation and the inheritance of polymorphic markers on the X chromosome."  Perhaps more intriguing was the fact that Hamer's purported discovery centered on the female sex chromosome, which came as a surprise to researchers who had long assumed that  male homosexuality -- being, after all,  a male orientation -- would trace through patrilineal genealogy.   

Hamer's announced discovery was received with predictably fawning and credulous attention, but as often happens when the big dogs serve up science in a soundbyte, the ballyhoo turned out to be premature. The evidence for Hamer's preliminary conclusion was statistically weak from the start, and with one controversial exception, the statistically suspect gene site has thus far eluded subsequent detection.

Still and again, it’s a maybe. And in fairness to Hamer, he never really claimed to have identified a “gay gene” as pop-media accounts invariably put it. Not exactly anyway; he merely claimed to have located a genetic frequency that was statistically correlated with a certain type of familially conspicuous homosexuality.

But the genetic hypothesis is the one that interests The Hog at present, so before writing off Hamer’s research as a dead letter, it is well that we should mention a couple of more recent lines of inquiry that have added fuel to the idea that homosexuality is indeed heritable, maternally descended, and potentially adaptive.

The latest and most promising research comes from geneticists with the National Cancer Institute (with Hamer's involvement), who recently published “A Genomewide Scan of Male Sexual Orientation” in the journal, Human Genetics. By looking at 146 families with two or more gay brothers, the research team reported on three loci that showed some indication of influencing homosexual orientation. In two of the three regions, the predisposition seemed to flow from either of the gay brothers’ parents, while the third seemed to be tied to an exclusively maternal lineage. Although this study was “the first genome scan for loci involved in the complex phenotype of male sexual orientation,” the findings remain very preliminary and have yet to be replicated.  But still.

A tangentially related study, published in 2004 in the Royal Society Journal: Biological Sciences, looked at the family structure of 100 heterosexual and 98 homosexual men and found that maternally linked female relatives of homosexual men had significantly more children than women in the maternal line of heterosexuals. The authors speculated that a gene for male homosexuality may paradoxically have survived by promoting greater “female fecundity,” with its homosexual expression being but a noisy and genetically innocuous dead-end.

Such an idea is consistent with the working hypothesis championed by the self-same "gay gene" gadfly, Dean Hamer, known as “selective maternal choice,” which holds that a maternally descended predisposition for heterosexual “overloving” among women might occasionally be expressed in male children who inherit their mother’s genetically advantageous sexual orientation.  By most accounts, Hamer fashioned his idea as a post-hoc addendum to his initially promising genetic investigations, but by shifting the focus from patrilineal models of inheritance -- where stability problems loom largest -- Hamer's idea represents an innovative departure in evolutionary speculation that may be revisited if  the ongoing genetic studies reveal a genetic link in female chromosome.   

So the jury is still out.  But the treasure hunt for a gay polygene continues. I don't know if Lloyds has laid odds, but researchers lead by Northwestern University's beleaguered but stalwart sex researcher, J. Michael Bailey, have undertaken a major study to determine whether the loci identified in Hamer's prematurely celebrated findings can be vindicated.  It will be a few years before the results are in, but the verdict -- at least with respect to chromosome Xq28 -- should be dispositive.  Wait and see.    

Even if the gay gene business doesn’t pan out, the evidence that gayness has a biological component is difficult to deny. The cumulative weight of twin studies suggests that anywhere from 30% to 50% of male sexual orientation is rooted somewhere in the biological mix, and as Salk University geneticist Simon LeVay has demonstrated, there are a host of anatomical and neuro-physical correlates to differentiate gay bodies and brains from those of the breeding herd. Most notably, there is a marked difference between gay and straight men in the size and structure of the hypothalamus.  Which is more than significant, since hypothalamic functioning is known to play a major role in the regulation of sexual desire. 

Still, a strictly genetic interpretation of the twin data is confounded by the fact that monozygotic twins share the same intrauterine environment where extra-genetic causes may lurk, and the fact that gay men tend to have smaller hypothalami  neither obviates nor predicts a genetic origin. It could still turn out that gayness is triggered by a hormonal imbalance as proponents of  certain theories of prenatal “inversion” have long speculated. 

Or -- and this is where things get really interesting -- homosexuality could be germ-borne.

Seriously.

In one of the more provocative theories to set off alarms, it is posited that homosexuality may result from some unknown form of pathogenic transmission. The idea has been prominently advanced by the Amherst College biologist Paul Ewald and maverick physicist-biologist Gregory Cochran, who set off the initial depth charge when their heterodox musings were prominently featured in Judith Hooper's 1999 Atlantic Monthly article, "A New Germ Theory."

While Cochran has remained the most tenacious (and charmingly impolitic) bully for the "gay germ" idea, Ewald, who literally wrote the book -- a  book, anyway -- on the Evolution of Infectious Disease, has taken the more diplomatic tack. "It's a very sensitive subject," he volunteered in Hooper's article,

and I don't want to be accused of gay-bashing. But I think the idea is viable. What scientists are supposed to do is evaluate an idea on the soundness of the logic and the testing of the predictions it can generate.

There are a couple of ways it might have happened.

In one version, a genetic predisposition for homosexuality might have been selected because it provided resistance against some harmful strain of infectious disease, much the way the sickle cell gene – potentially deleterious in itself – provides resistance to malaria.

In the another scenario (favored by Cochran), homosexuality would itself be caused by a brain infection of some kind, probably in-utero or during infancy.  Steve Sailer's VDARE article, "Gay Gene or Gay Germ?," summarizes:

It's probably not a venereal germ, but maybe an intestinal or respiratory germ. If it spreads like the flu, and if it needs to strike at a particular stage of development before or shortly after birth, then more male homosexuals might be born in one season than another, just as more schizophrenics are born in late winter and in early spring, especially in cities with cold winters.

So far, the speculation about seasonality hasn't panned out, but before writing off the germ theorists, it is well to consider one of the more curious exhibits in the annals of unconventional zoology: the gay sheep.  "Preferential homosexuality," as Cochran emphasizes, "is very rare. The only two species known to exhibit this behavior, at the-few-percent level, are men and sheep. It may be worth noting that men and sheep have often been found in close association." (Insert Brokeback Mountain joke here).

This isn't another case study of biological exuberance being expressed in promiscuity with an occassional misfire. No, these rams are  full-on homos.  Line up a row of estrous ewe poon, throw a ram's rear end somewhere in the queue, and the gay sheep will mount the ram nearly every time.  It drives farmers crazy.

As it turns out, and as Cochran is quick to emphasize, studies of  gay sheep brains point up a number of similarities with homosexuality in humans.   Gay sheep brains reveal reduced testosterone levels, when compared with their ewe-humping brethren, and there is a consistent and substantial difference in the structure of the hypothalamus, which is consistent with  Simon LeVay's aforementioned research documenting brain dimorphism in straight and gay men.

The pathological structure of such observed brain irregularities is of special interest to the gay germ guys because the affected brain regions are especially susceptible to infection.  As Agnostic points out in his recent cerebrations on the related - and equally speculative - subject of  "Genius Germs," the "blood brain barrier," which generally protects our grey matter from harmful pathogens offers no such armor for the hypothalamus, making it a fertile ground for germs to work their peculiar magic. 

More fundamentally, the germ theorists play up the ostensible fitness costs associated with preferential homosexuality to argue that infection is simply more parsimonious as a default hypothesis.  Cochran puts the matter bluntly: 

There are plenty of syndromes with comparable evolutionary cost, but almost every one is caused by an infectious organism, a parasite. Most are somatic, but some involve behavioral change. Tertiary syphilis made lots of people act odd, act in ways that detracted from fitness. If lots of people are sterile, it's infection. If lots of people go blind ( in old-fashioned surroundings), it's infection ( river blindness or trachoma) . If lots of people are deaf, it's infection ( rubella, mainly) . If lots of people have liver failure, it's infection (hepatitis B or C) (or something fairly new like distilled alcohol). if lots of people have crappy lungs, it's tuberculosis ( or a new agent like cigarettes). That's the way things work. The big syndromes that reduce fitness are caused by infection or new environmental insults - but the greatest of these is infection. 

The power of natural selection decreases with age, especially after the reproductive years, so bad stuff happening to 80 year olds is no anomaly. If homosexuality hit at 85, like Alzheimer's, it wouldn't be anomalous. But of course that is not the case. It's an evolutionary anomaly. Almost all evolutionary anomalies of comparable size are caused by infection. It's the way to bet.

Of course, the notion that gayness could have a pathogenic rather than genetic-adaptive origin is about as gauche as it gets, but it’s not as preposterous as you might wish. Keep in mind that until a few years ago, the idea that peptic ulcers were infectious was roundly dismissed as rank heresy, but then a couple of tenacious scientists came along to claim a Nobel Prize for proving just that.  And homosexuality isn't the only neuro-behavioral condition to be considered within such a paradigm; pathogenic factors are widely suspected to be involved in the etiology of such conditions as schizophrenia and narcolepsy. 

I don't know.  Cochran is one cocksure motherfucker, but there's no question he has the brains to back it up.  I'd think ten times before betting against him, even if he were alone in speculating about the link between pathogens and sexual orientation. Which he isn't.  But nor would I bet against complexity. The big picture reductionism, which is generally laudable, always seems a bit pat when applied to human psychosexual proclivities. And I suppose I might find the germ noodlings more compelling if gayness was expressed as more of a specific or narrowly-fixated neurological quirk -- like narcolepsy -- without all the temperamentally distinctive baggage.  But what do I know?  Neurological damage can manifest in some remarkable ways.

Further complicating matters is the fact that homosexuality is far from a monomorphic predisposition. Sex researchers argue over the finer distinctions, but the most conservative nosology tells us there are at least five distinctive types of male homosexual orientation, all or some of which may yield to different etiological explanations. Independent researcher Louis Berman claims to have classified more than 30 discretely characterized "homosexualities," which seems nuts until you read his compiled case studies.

So, it could be that your stereotypical flaming community theater habitué is a hormonally inverted case, while your typical truckstop bear owes his sexual pedigree to some confluence of genetic factors; and those Project Runway finalists, maybe they'll turn out to be the pathogenic cases.  What's more, while Freud and Foucault have fared none too well under the onus of behavior genetics, there may yet be a few typological crumbs for the psychoanalytic or social constructivist crowd to fight over. And lets not forget the economists. 

I'm just saying, this is complicated business.

And I don't pretend to have the answers.  Nor do I apologize for asking the questions, and entertaining the possibilities.  Science will continue to prod at the hard sociobiological questions, and the truth that ultimately emerges may prove to be just as complex, with something to disappoint everyone. Which would be just fine with me. It's a mixed up, muddled up, shook up, world, abounding with genuine mysteries, and surprises, and gay sheep. That's what keeps things interesting.

Next question, please.