4 Reasons Why Pro-Homosexual Activists Should Think That Scientists’ Alleged Discovery of an ‘Evolutionary Advantage for Homosexuality’ Is Nothing to Write Home About
Matthew J. Bell
In a recent post, one writer for the IFLScience weblog, which site is presumably an outgrowth of Elise Andrews’s provocatively-named “I F*****g Love Science” Facebook interest group, rhapsodizes about the supposed recent “discovery” of an “evolutionary advantage for homosexuality.” (<http://www.iflscience.com/plants-and-animals/scientists-discover-evolutionary-advantage-homosexual-sex>.)
Before I enumerate four reasons why this headline is overambitious and not supported by the evidence, let me briefly catalog a few of the issues about which I am not mainly interested.
Firstly, obviously the blogger assumes that there is some sort of genetic basis for homosexuality. None of my “four reasons” will contest this. I hasten to add, though, that this is not because the claim is incontestable.
As things stand presently, this is (at best) simply an assertion. In the language of philosophy, an “assertion” is a proposition that is advanced as true without (adequate) argument or evidence in its support. It is not the job of the hearer to argue against an assertion. It is, rather, the job of the speaker to provide adequate argument and evidence for her assertions. Without such argument or evidence, the hearer is under no rational obligation to respond.
To be sure, there is, among many people, a hope that a “‘gay’ gene” will be found. Indeed, it is true that there may be, among some, an expectation that one will be found. However, there is a hope and an expectation among certain children that they will be visited by the tooth fairy, Santa Claus or the Easter Bunny. Unless they are rooted in rational evidences, these hopes and expectations have little more than emotional content.
There is no demonstrable “‘gay’ gene.” In the words of the organization NARTH: “There is no evidence that shows that homosexuality is simply ‘genetic.’ And none of the research claims there is. Only the press and certain researchers do, when speaking in sound bites to the public.” (“Is There a ‘Gay Gene’?” NARTH, <http://www.narth.com/docs/istheregene.html>.)
But let this pass. For the sake of argument, I will grant that there is a “‘gay’ gene.”
Secondly, in my “four reasons” I am not going to fuss about any misstatements of fact made by the blogger. For example, in her opening sentence, Ms. Alford writes that “…researchers may have just found a benefit conferred by homosexual sex that could offer an explanation as to why this behavior has persevered…”.
The problematic bit is the phrase “conferred by homosexual sex.” Of course, none of the research cited by Alford comes even remotely close to claiming that any survival advantage is “conferred by homosexual sex.” Rather, the hypothesis is entertained that same-sex sexual behaviors (SSBs) are expressions of a genotype – call it the “‘gay’ gene” – that also expresses itself in some other, hypothetical characteristic and that this characteristic is supposed to confer survival advantage.
The difficulty here is somewhat subtle. Let me try to sharpen my point with the help of an analogy.
Consider sickle cell anemia (SCA), a disorder afflicting mainly blacks in which the sufferer may end up with low levels of bio-available oxygen due to an abnormality in the shape of his or her red blood cells. Specifically, the SCA sufferer’s red blood cells have a “sickle”-shape (hence the name). If and when low oxygen conditions arise, the SCA sufferer is said to be undergoing a “sickle cell crisis.” Often these crises can be fatal. In any event, SCA sufferer’s life expectancy is shorter than that of a non-sufferer, ceteris paribus. It follows, therefore, that it would be better to not have the SCA genotype than to have it.
But according to experts on SCA, it is also true that the genotype for SCA confers a survival advantage. To be exact, a person who has the SCA genotype (whether homo- or heterozygously) has a well-defined survival benefit. “Producing altered hemoglobin can be beneficial for inhabitants of countries afflicted with falciparum malaria, an extremely deadly parasitic disease. Sickle blood cells ‘collapse’ around the parasites and filter them out of the blood. Thus, people who carry the sickle-cell allele are more likely to recover from malarial infection.” (Ilona Miko, “Genetic Dominance: Genotype-Phenotype Relationships,” Nature, 2008, <http://www.nature.com/scitable/topicpage/genetic-dominance-genotype-phenotype-relationships-489>.)
However – and this is my complaint about Alford’s prose – saying that the SCA genotype confers an advantage in terms of surviving malaria is not the same thing as claiming that the sufferer’s anemia is itself responsible for conferring said advantage. It’s not the anemia that confers the relevant advantage. The anemia is a possibly life-threatening condition and is an obvious survival disadvantage. Instead, what we mean to say is that the underlying genotype that produces the disadvantageous anemia also produces an advantageous protection against malaria.
Similarly, saying that a (hypothetical) “‘gay’ gene” confers an advantage in terms of heightening fertility in female offspring is not the same thing as claiming that the “homosexual sex” acts are themselves responsible for conferring said advantage. It’s not the homosexual sex that confers the relevant advantage. The homosexual sex – at least insofar as it is exclusive – is an obvious survival disadvantage. (This is obvious, even if it is not “politically-correct.” After all, there would be no “paradox” to resolve if phenotypic “homosexual traits” were conducive to reproductive success.) Instead, what we mean to say is that the underlying genotype that produces the disadvantageous homosexuality also (at least hypothetically) produces an advantageous increase in the fecundity of female offspring.
But let’s let this pass also. After all, rephrasing the point alleviates Alford’s error. So we can substitute my (albeit more prolix) expression, above, for Alford’s (which is pithy but technically inaccurate).
Thirdly, I will not be challenging the evolutionary assumptions of the article. This is not because I do not think any such challenge to be worthy, but because my “four reasons” all stand on their own even if the actual, factual claims of the article turn out to be correct.
Fourthly, readers will soon encounter numerous instances of the phrase “same-sex sexual behaviors” (sometimes abbreviated SSBs). I will not pick nits over the operative definition of these SSBs, however. Again, this is not because I think that there are no interesting questions in the vicinity (I direct readers’ attention to the fact that one of the supposed indicators of homosexual inclinations in fruit flies was flies that “sing” to other male flies), but because I think that my “four reasons” put the kibosh to any hope that this information will aid “pro-homosexual” activists – even if the information presented is true.
With this much ground cleared, let me proceed to the heart of the matter. Considering what Alford has written – and granting the truth of it – one may still be left with the impression that it’s much ado about nothing. I will give four reasons for this. (Some of the reasons fix upon peripheral points while others focus on main points. In other words, not all of these reasons will be equally weighty. They are all of some intrinsic interest, however. Or at least so say I.)
NUMBER ONE: There is a significant difference between a “discovery” and a hypothesis.
The IFLScience article headline grabs readers’ attention by asserting, basically, that things are settled: “Scientists Discover Evolutionary Advantage for Homosexuality.” As the kids say, “It’s a done-deal.” Jonas Salk discovered a vaccine for polio; Albert Szent-Györgyi discovered vitamin c; William Herschel discovered Uranus; and “Scientists” have “discovered an Evolutionary advantage for homosexuality.” End of story.
But hold on; things are not so clear-cut. Alford’s text body is far more sober than the title-line. (It is possible that she was not the one who developed the headline.)
She writes: “[R]esearchers may have just found a benefit conferred by homosexual sex that could offer an explanation as to why this behavior has persevered, at least in one species. According to a new study in fruit flies, not only does same-sex sexual behavior seem to be heritable, but females with a genetic makeup associated with this trait actually display higher reproductive rates, which is an evolutionary advantage.”
Got that? It is possible – though by no means transparent – that there is a “benefit” to possessing a (hypothetical) genotype that expresses itself partially in same-sex sexual behavior (SSB). This is based upon a study of fruit flies in which SSBs “seem to be” – but still and all might not actually be – “heritable.” Now beside the fact that the extent to which animal studies are even potentially able to tell us anything about human sexual behavior is highly controversial, to hear Alford tell it, the scientists who conducted the relevant study are not even sure about there being a genetic basis to what the fruit flies are doing.
In any case, in the interest of accuracy, the blog post should be retitled “Theorists Speculate About a Possible Evolutionary Advantage for a Hypothetical Homosexual Genotype.” Though, I admit: The revised headline is probably not going to be as successful a piece of “click-bait.”
NUMBER TWO: The author implicitly acknowledges that 99.8% of animal species have no observed traits that could be fairly glossed as “same-sex sexual behaviors.”
Of course, Ms. Alford does not put it in these terms. She writes that “homosexual behaviors …[are] observed in more than 1,500 species.” This fact (if it be such) is really not that impressive, however.
If one Googles a search string such as “how many different animal species are there in the world?” one finds that amongst the top results is Discovery’s article titled “8.74 Million Species on Earth.” (Tim Wall, Aug 23, 2011, <http://news.discovery.com/earth/plants/874-million-species-on-earth-110823.htm>.)
In it, we read the following. “Eight million, seven hundred and four thousand eukaryote species share this planet, give or take 1.3 million. …There are 1.2 million species officially registered in the Catalogue of Life and the World Register of Marine Species.”
Excluding “chromists,” “fungi,” “plants” and “protozoa” (that is, merely considering “animals”) the approximate species count is 7.77 million, “of which 953,434 have been described and cataloged.”
Contemplating only the 953,434, we see that the 1,500 species which have so far displayed SSBs amount to 0.1573% (1,500/953,434) of the total number of animal species that have been “described and cataloged.” This means that the remainder – roughly 99.8427% – either have no SSBs at all, have no observable SSBs or have yet to have their SSBs observed.
Taking stock of what we currently know, therefore, the percentage of animal species with observable SSBs is vanishingly low. Anyone who wishes to make a case for the prevalence, throughout the animal kingdom, of SSBs presently can do no better than to premise his or her argument upon expectations, hopes, speculations or wishes.
For those whose alpha and omega is supposedly self-limited to what “science says” – and isn’t this the mentality of the “IFL Science” brigade? – there is really nothing to say about SSBs amongst animal species except the following. Either one should admit that the current state of the evidence shows that fewer than 1% of species display SSBs, or one should profess more or less total ignorance about the matter (on the notion, perhaps, that the above-mentioned “descriptions” and “catalog” entries simply have not been robust enough to really speak to the question of sexual behavior).
From the point-of-view of “pro-homosexual” activism, though, the preferable route seems to be to simply concede that we simply don’t know.
NUMBER THREE: The fruit flies in which “same-sex sexual behaviors” were observed were (a.) inbred (b.) in captivity.
Moving from what we don’t know to what we do know takes us into interesting territory. According to the study’s abstract, the researchers sample set was: “…50 inbred lines derived from a wild population…”. (Jessica L. Hoskins, Michael G. Ritchie and Nathan W. Bailey, “A Test of Genetic Models for the Evolutionary Maintenance of Same-Sex Sexual Behaviour,” Proceedings of the Royal Society, May 27, 2015, <http://rspb.royalsocietypublishing.org/content/282/1809/20150429>.)
Firstly, this means that the observed fruit flies were not necessarily behaving as they would in the wild. How much weight can be placed upon claims about the “naturalness” of such-and-so behavior when that behavior was observed under artificial, laboratory conditions?
Maybe the observed SSBs also occur “in nature,” maybe not. But we need a lot more than what we have in order to make that determination.
Secondly, as a different article puts it: “Inbreeding is generally frowned upon, even in the animal kingdom.” (Alex B. Berezow, “Female Fruit Flies Mate with Brothers, Dad,” Real Clear Science, Dec. 13, 2012, <http://www.realclearscience.com/journal_club/2012/12/13/female_fruit_flies_mate_with_brothers_dad_106423.html>.)
Maybe the observed SSBs would have been observed in the laboratory even if the relevant fruit flies had not been “inbred,” maybe not. But, again, we should require more by way of evidence before we simply accept that the behavior of “inbred” fruit flies tells us anything about the behavior of wild fruit flies.
Presumably, “pro-homosexual” activists are not trying to establish that SSBs can be artificially induced through selective breeding strategies (and, possibly, manipulating environmental factors). Presumably, activists are hoping that “science” will vindicate their “lifestyle choices” by justifying the label “natural.”
If so, they would be advised to look elsewhere than this study for support. Inbred fruit flies impelled to display SSBs (possibly for lack of options) in a contrived, laboratory environment hardly suffices to establish that any observed behaviors count as “natural.”
NUMBER FOUR: We should not miss the fact that the entire “evolutionary advantage” – however hypothetical – hinges upon “homosexuals” actually reproducing.
There is no getting around it. Exclusive same-sex sexual behaviors are a dead-end, in evolutionary terms.
This is why the blogger begins with the admission that the presence of SSBs is “an evolutionary paradox that’s frustratingly difficult for biologists to explain.”
Alford reports: “The final stage of the investigation involved performing experimental crosses of flies from both of these identified lines and examining the resulting offspring.” (Emphasis supplied.)
It does no good simply to allege that (the hypothetical, genotypic basis for) “homosexuality” confers an “evolutionary advantage” that is detectable in “resulting offspring” unless the “homosexuals” under review actually reproduce.
Readers find, at last, that the supposed “evolutionary advantage” is this: “Males with a genetic makeup associated with high levels of SSB produced female offspring with higher rates of reproduction, or fecundity.”
Notice a few things, however. In order for this alleged “advantage” to be displayed, “[m]ales with a genetic makeup associated with high levels of SSBs” have to reproduce. Not to put too fine a point on it, but obviously, if any male is going to reproduce then that male has to actually couple with a member of his species that is possessed of complementary sex organs. To be precise, ““[m]ales with a genetic makeup associated with high levels of SSBs” can only “[produce] female offspring with higher rates of …fecundity” if the relevant males do not exclusively engage in same-sex sexual behaviors.
If the relevant males are exclusive, practicing or non-practicing “homosexuals,” then it is clear that no offspring whatever will result and even the “evolutionary advantage” hypothesized by these researchers will come to naught.
What is there, then, for “pro-homosexual” activists to celebrate?
If we take the article’s claims at face-value, then what we “discover” is not any definite “evolutionary advantage,” but only a hypothetical one. Generally, this speculated advantage rests upon observations made about fewer than 1% of the animal species on the planet. Specifically, at least as formulated in the article, the hypothesis turns upon various “same-sex sexual behaviors” (including “singing”) observed of inbred fruit flies in a laboratory setting. Finally, even if (contrary to my intuitions) these shaky foundations hold, one does not get to the conclusion that exclusive “same-sex sexual behavior” is somehow “beneficial.” After all is said and done, the male “homosexuals” in view still have to mate with females in order to produce the offspring that, the study alleges, might end up enjoying the conjectural survival advantage.
Personally, I do not see much here that would actually be of interest to “pro-homosexual activists.”