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From The Huffington Post:

For even without a causal link established between homosexuality and population management, the obvious reduction in population growth attributable to homosexuality by itself indubitably works to preserve the species. (Emphasis mine)

So "homosexuality by itself indubitably works to preserve the species", really?

Thus, my question is: Does homosexuality work to preserve the species?

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    I would argue that this question has an invalid premise. Natural selection operates at the level of genes, and is not "concerned" with preserving a species. en.wikipedia.org/wiki/Gene-centered_view_of_evolution#Overview Recent evidence is that homosexuality is not genetically determined but epegentic. genengnews.com/gen-news-highlights/… This would make any sort of idea that there is a selective pressure FOR homosexuality false. – Robert Kaucher Jan 2 '13 at 21:49
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    I agree with Carlo here. The claim could be "rainfall works to preserve the species" and it would still be valid. There is no need to even accept evolution at all to make this a valid claim (remember: valid, does not mean necessarily correct!) – Sklivvz Jan 3 '13 at 13:09
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    Noting the new bounty, I maintain "preserving the species" has no clear meaning, so you won't get any high-quality, definitive answers. Which of the following counts as "preserving a species"? 1) Increasing the population? 2) Decreasing the population? 3) Preserving the current distribution of genes? 4) Changing the relative distribution of genes (as homosexuality is alleged to do, and thus changing (not preserving) the species)? Does the homosexual behaviour of chimps preserve the species? If so, why aren't we all still preserved at the same common ancestor? – Oddthinking Jan 7 '13 at 11:54
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    @Carlo_R. The problem with the question is that there is no evidence to support the claim and therefore there is no satisfactory "yes" answer. We know some homosexuals still reproduce, we know that the human population is still growing exponentially, and we know that in historical examples of out of control populations in other mammals their numbers are regulated by things like famine, disease, and/or increased predation NOT by increased instances of homosexuality. We cannot prove a negative. There is no evidence to support the indubitable claim in the question. – Robert Kaucher May 20 '13 at 19:00
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    Maybe I'm missing something, but how the "gene" would be selected if it existed to limit the expansion of population? Either it works then it is not selected (limited reproduction) or it doesn't work and it is selected (normal reproduction)... quite a paradox. – Zonata May 20 '13 at 19:30
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Two things that are often overlooked in discussions of evolution, particularly when it comes to sexual behaviour, are sexually antagonistic traits and epigenetics. Recent studies indicate that homosexuality may be due to a normally beneficial epigenetic mechanism that occasionally malfunctions. If this is the case, then homosexuality is an abnormal consequence of a beneficial trait, and so there is no reason it should have been selected out of the gene pool.

W. R. Rice et al., “Homosexuality as a consequence of epigenetically canalized sexual development,” The Quarterly Review of Biology, 87:343-368, 2012

  • What's the format for citation? There is a paper cited at the bottom of my second link. – Isaac Jan 3 '13 at 22:39
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    Hello, Isaac and welcome to Skeptics! Great first answer. – Sam I Am Jan 4 '13 at 5:45
  • I’m averse to words such as “abnormal” and “beneficial” which clearly carry judgement and normally have no meaning in biology – of course we speak of “averse” conditions in the case of an illness but redefining homosexuality as an illness is something we’ve transcended. – Konrad Rudolph May 20 '13 at 18:40
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    @KonradRudolph According to Merian-Webster abnormal signify: deviating from the normal or average. However, I agree that to most of us, it carries a pejorative meaning. – Zonata May 20 '13 at 22:03
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    @KonradRudolph It is the average, thus the majority. In the case of sexual orientation, a very strong majority of persons are heterosexual. To me it does not carry any other meaning than that. But again, I agree with you that to most being abnormal is pejorative thus it is a word I use carefully in daily life. – Zonata May 21 '13 at 0:45
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Due to some very apt criticism regarding my comment on the question I am going to rephrase it as an answer. It is not so much that the question has an invalid premise, but that the cited article that generated the question is based on an invalid premise.

We know as a fact that homosexuals do conceive children.1 The idea that they do not is false and the idea that they did so less than heterosexuals in the Environment of Evolutionary Adaptedness is likely completely untestable. We would really need research to test this claim and none exists. The notion that this idea is in any way indubitable is just foolish. And consider this: if that is what homosexuality is supposed to be "for", then it is doing a very, very poor job considering the continued exponential growth of the human population2. Also, recent evidence is that homosexuality is not genetically determined but epigentic. This would make any sort of idea that there is a selective pressure FOR homosexuality false because it is not directly tied to genes. This means Natural Selection could not "use" it to "better" the species by making it more "stable".

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If homosexuality cannot be shown to control population growth, what do we know DOES control population growth? Within other animals we know it to be things like disease (viruses, bacteria, parasites, etc), famine, and increased predation3. I see no reason to assume that humans are exempt from most of these and no evidence to conclude that we have evolved homosexuality as a method of population control, as again, current evidence shows homosexuality to be epegenetic in origin.

I imagine the author of the article thinks himself very progressive but what he is doing is actually harmful. The article seems to imply that homosexuality requires some sort of natural "utility" to make it "ok" or acceptable. This is just an extension of, or perhaps a reversal of, the Naturalistic Fallacy. It seems to be promoting the idea that if something is right or ok, it must be natural because what is natural is right, good, or ok. But if that is the only basis for why homosexuals must be treated with respect and not discriminated against then it rests on a very shaky foundation. If homosexuality is scientifically demonstrated to be a "side-effect" of a natural process, as it seems to be from recent research, then the idea that it is "natural" is eroded. If we as a society are going to make the choice that people should be respected and not discriminated against based on sexuality then we need to do so on real and not fallacious reasoning.

1 Supporting Claim that Homosexuals Conceive Children

Notice I am not claiming all homosexuals conceive children nor that homosexuals conceive children at the same rate as heterosexuals. This American Life: Double Lives

Gay man who fathered child for lesbians wins right to more access

Oscar Wilde, who is generally considered to have been a homosexual and not bisexual had two children. It strikes me as odd that people demanded a reference to this as the claim is, in my opinion, as easily verifiable as to be taken for granted since there have been so many instances of this throughout history.

2 Regarding the Exponential Growth of the World Human Population

In addition to the Wikipedia links given in the text, please see the UN's World Population Prospects site for the statistics regarding historical world population values and Human Population Growth for details regarding the mathematics for demonstrating that the world population has been growing exponentially for several centuries.

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    The interesting question isn't anything to do with the morality of homosexuality, but with its evolutionary origin. How can something as superficially non-reproducing develop or persist given the normal rules of (crudely) the winner produces the most offspring? There are speculative theories. One argues that homosexual genes improve parenting (either via group-selection where groups with some homosexuals do a better collective job of parenting, or the genes for homosexuality confer better parenting skills on the non-homosexuals who carry them). – matt_black Jan 3 '13 at 16:20
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    @matt_black To clarify a point you clearly understand: It's not "speculative theory" that genes that improve overall population success may be selected for even if those genes leads to some individuals being less likely to breed (as any ant will attest). The "speculative theories" are that homosexuality may involve such genes. – Larry OBrien Jan 3 '13 at 19:36
  • The paragraph on morality was added simply as a further criticism of the article and does not directly pertain to the question asked. – Robert Kaucher Jan 3 '13 at 20:01
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    @Larry: That's slightly misleading. The successful genes aren't those that lead to overall population success (even at the expense of the individual). The successful genes are those that lead to THOSE genes having population success. The "faulty premise" being that the genes are trying to "preserve the species over the individual" rather than "preserve themselves over the individual". – Oddthinking Jan 3 '13 at 20:55
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    @denten - Could you site the rule as I don't see anything in the FAQ that would lead me to believe that my answer is some how against the rules of the forum. If it your argument is valid, though, I will remove it. – Robert Kaucher May 21 '13 at 1:47
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I find this question quite frustrating. It is a complete train-wreck, despite the OP's claims that it is "one of the better ones I've seen". It has received way too many upvotes from the community, despite comments pointing out some of its flaws. The answers have pussy-footed around this. It is time to go for the jugular.

The claim makes no sense whatsoever. It isn't just wrong because of its false premises and non-sequiturs. It is meaningless.

I shall use an extended analogy to try to explain this. Imagine I made the claim that:

The addition of the preservatives of sugar and formaldehyde to fruit cake have indubitably worked to preserve the recipe over the years.

You would be flabbergasted. This fruit-cake claim is riddled with errors. So is the original claim.

Unclear Term

What does "preserve the recipe" mean? Does it mean keep the recipe unaltered? Does it mean ensuring the recipe exists in the future? Does it mean ensuring the recipe grows in popularity? Does it mean ensuring the popularity remains the same?

If it means keeping the recipe unaltered, then the act of altering it clearly doesn't preserve the recipe. Likewise, if "preserve the species" means keeping the relative distribution of genes in the gene pool the same, introducing a genetic change doesn't preserve the species. [No references. I'm arguing about (lack of) definitions here.]

Further, the fact that homosexuality appears in other related species [Example], shows that homosexuality doesn't somehow stop evolution from happening, in the same way having sugar in the recipe obviously hasn't worked to keep recipes the same, or there would only be one sugary cake. Instead, cake recipes keep changing, and fruit cake recipes keep changing - which is to say, new mutations appear, and the relative populations of the different recipes change. And species with homosexual behaviours keep evolving.

If it means ensuring the popularity/population remains the same, which is implied by "reduction in population growth", then the species is completely failing to be preserved. The population is growing, especially since the advent of homosexuality - i.e. the beginning of homo sapiens. [Ref] This weird argument defends a demonstrably false conclusion.

False Premise 1

Fruit cakes don't contain formaldehyde. [Reference: I just made the claim it up, and I really hope it isn't true.]

Homosexuality isn't a simple matter of genetics. Reference.

Using a purely genetic argument to discuss the advent of homosexuality is flawed.

False Premise 2

Even if fruit cakes did contain formaldehyde, it doesn't mean that it would act as a preservative in cakes. That would have to be shown empirically.

Even if homosexuality was pure genetics, it doesn't mean that there is a reduction in population growth. That would have to be shown, and is possibly wrong. [Ref: one possible counter-hypothesis: kin selection]

Mixing of Levels

Even if cakes did contain formaldehyde and formaldehyde was a cake preservative, there is a huge difference between preserving an individual cake and preserving a recipe. They are at different levels of abstraction.

The claim makes a similar (common) error of confusing how evolution works - the unit of evolution is the gene, not the species. Evolution works to preserve (i.e. increase the relative population of) the successful genes, even at the expense of the species. [Reference: The Selfish Gene] The suggestion that group selection might occur through natural selection is heavily disputed.

This error in levels is further explained by evolutionary expert, Richard Dawkins, in his video addressing a similar question: "Is Homosexuality Nature’s Population Control?"

Conclusion

There are several false premises in the claim, showing a lack of understanding of populations and the biology of homosexuality. There is fault logic in the claim showing a lack of understanding of evolution. There is no clear definitions of the terms, making the question meaningless.

I hope I have clearly demonstrated: both the original question and my invented analogous statement are fruit-cake claims, riddled with errors.

  • Please reference that "Using a purely genetic argument to discuss the advent of homosexuality is flawed" follows from "Homosexuality isn't a simple matter of genetics". A not being completely explained by B, doesn't imply to me that it's flawed to talk about the way that B affects A in isolation from other causes. It happens in science a lot. – user5582 Nov 1 '13 at 17:00
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+50

My answer would be no, but it is not clearly proved nor provable (I don't see how it could ever be proven). I wanted to take a different angle than the other answers and I hope it will help the readers to draw their own conclusions.

If there is a correlation between population control and homosexuality, there should also be a correlation between the homosxuality rate through the ages. Sadly, we were not there to poll the population in ancient times even though it is known that homosexuality was present and accepted in ancient Greece [1] for instance. However, we do have surveys from the early 50's when the world population was only 2.5 billions compared to today 7 billions. So, looking to the research papers, can we see a correlation?


The surveys in scientific literature

1948 [2] (World pop.: around 2.4 billions)
Had homosexual experience: 37%
More or less homosexual: 10%
Exclusively homosexual: 4%

1974 [3] (World pop.: around 4 billions)
Had homosexual experience: 27%
More or less homosexual: 7%
Exclusively homosexual: 2-3%

1977 [4] (World pop.: around 4.1 billions)
More or less homosexual: 3.1%
Exclusively homosexual: 1.3%

1989 [5] (World pop.: around 5.3 billions)
Had homosexual experience: 20.3%
More or less homosexual: 3.3%

1990 to 1995 [6-12] (World pop.: around 5.3-5.7billions)
Had homosexual experience: 9-20.8%
More or less homosexual: 2-9%
Exclusively homosexual: 1-4%

2002 [13] (World pop.: around 6.5billions)
Bisexual: 1.8% (including bisexual)
Exclusively homosexual: 2.3%
Other: 4%

2006-2008 [14] (World pop.: around 6.8billions)
Had homosexual experience: 4-6%
Exclusively homosexual: 2-4%

Considering the scientific surveys, if there is any correlation to make between homosexuality rate and population, it would be that it is decreasing as population grow. However, it is widely accepted that the decrease after early research by Alfred Kinsey is more related to wrong estimates in the first place [15]. Moreover, we can see that the rate vary a lot between different surveys reflecting inherent uncertainty of the sexual orientation.


Per country

We could also look into the census done by different countries to see if the densily populated ones show higher homosexuality rate. Warning! depending on the country, the statistics are more or less accurate.

Canada [16] - Density: 3.41/km^2 - Homosexuality rate: 1.1% - Bisexual: 0.9%
United States [17] - Density: 34.2/km^2 - LGBT rate: 3.4%
China [18] - Density: 139.6/km^2 - Homosexuality rate: 0.8-4%
United Kingdom [19] - Density: 255.6/km^2 - Homosexuality rate: 1.1% - Bisexual: 0.4%
French Republic [20] - Density: 116/km^2 - Homosexual couples: 0.6% (no data on homosexuality)
Norway [21] - Density: 255.6/km^2 - Not Hetero: 1.1% - Do not wish to answer: 5.9%


In conclusion, from the statistics, there does not seem to be any link between the popuplation number and density and the homosexuality rate. Therefore, it does seem to contradict the claim that homosexuality exist to control the population growth.


References

[1] Davidson, J. (2007). The Greeks and Greek love: a radical reappraisal of homosexuality in Ancient Greece. Weidenfeld & Nicolson.

[2] Kinsey, A., Pomeroy, W., and Martin, C. (1948). Sexual Behavior in the Human Male. Philadelphia: W.B. Saunders.

[3] Hunt, M. (1974). Sexual Behavior in the 1970's. New York: Dell.

[4] Pietropinto, A., and Simenauer, J. (1977). Beyond the Male Myth. New York: Times Books.

[5] Fay, R., Turner, C., Klassen, A., and Gagnon, J. (January 1989). Prevalence and patterns of same-gender sexual contact among men. Science 243, 338-348.

[6] Harry, J. (1990). A probability sample of gay males. Journal of Homosexuality 19(1), 89-104.

[7] Smith, T.W. (1991). Adult sexual behavior in 1989: Number of partners, frequency of intercourse and risk of AIDS. Family Planning Perspectives 23(3), 102-107.

[8] Janus, S., and Janus, C. (1993). The Janus Report on Sexual Behavior. New York: John Wiley & Sons.

[9] Billy, J., Tanfer, K., Grady, W., and Klepinger, D. (1993). The sexual behavior of men in the United States. Family Planning Perspectives 25(2), 52-60.

[10] Taylor, H. (1993). Number of gay men more than four times higher than the 1 percent reported in a recent survey. The Harris Poll #20. New York, NY: Louis Harris & Associates.

[11] Laumann, E., Gagnon, J.H., Michael, R.T., and Michaels, S. (1994). The Social Organization of Sexuality: Sexual Practices in the United States. Chicago: University of Chicago Press.

[12] Sell, R. L., Wells, J. A., and Wypij, D. (1995). The prevalence of homosexual behavior and attraction in the United States, the United Kingdom and France: Results of national population-based samples. Archives of Sexual Behavior 24(3), 235-248.

[13] Mosher WD, Chandra A, Jones J. Sexual behavior and selected health measures: Men and women 15–44 years of age, United States, 2002. Advance data from vital and health statistics; no 362. Hyattsville, MD: National Center for Health Statistics. 2005.

[14] Chandra A, Mosher WD, Copen C, Sionean C. (2011)Sexual behavior, sexual attraction, and sexual identity in the United States: Data from the 2006–2008 National Survey of Family Growth. National health statistics reports; no 36. Hyattsville, MD: National Center for Health Statistics.

[15] McWhirter, D., Sanders, S., and Reinisch, J. (Eds.). (1990). Homosexuality/Heterosexuality. The Kinsey Institute Series. New York: Oxford University Press.

[16] http://www42.statcan.gc.ca/smr08/2011/smr08_158_2011-eng.htm

[17] Gates, Gary J.; Newport, Frank (October 18, 2012). "Special Report: 3.4% of U.S. Adults Identify as LGBT".

[18] http://www.chinadaily.com.cn/english/doc/2004-12/02/content_396559.htm

[19] http://www.ons.gov.uk/ons/rel/integrated-household-survey/integrated-household-survey/april-2011-to-march-2012/stb-integrated-household-survey-april-2011-to-march-2012.html

[20] http://www.insee.fr/fr/themes/document.asp?ref_id=ip1435

[21] http://www.ssb.no/a/english/publikasjoner/pdf/rapp_201038_en/rapp_201038_en.pdf

  • 1
    An excellent answer. – Robert Kaucher May 21 '13 at 1:41
  • (1) These survey comparisons across time and across countries probably tell us more about the societies and their taboos and the assumptions made in the surveys than it does about the base-rate of same-sex attraction. (2) you haven't shown a lack of causality. Has decreased prevalence lead to population growth? (No, but you haven't shown that.) – Oddthinking May 21 '13 at 4:49
  • @Oddthinking (1) How would you expect one to obtain a more accurate portrait of homosexuality than looking through the scientific literature? (2) I have shown there is no link between both. Some time population have grown and the rate increase and other time it is the contrary. What more would you need to be convinced? Some scientist drawing the conclusion for you and writing it in a paper? Moreover, OP claims said "obvious reduction in population growth"... not the opposite. – Zonata May 21 '13 at 5:09
  • @Zonata: We need to accept that sometimes the scientific literature does not or cannot answer a question. You may have the best possible historical data available AND cannot draw conclusions because of the size of the unknowns. (I am trying to remember the name of this logical fallacy for further reading, but I am drawing a blank.) – Oddthinking May 21 '13 at 5:12
  • @Oddthinking Yes, and I do agree with that. But what kind of answer would be good for such question? If the matter is not provable than is the question really pertinent? As a skeptic, I always seek for the most plausible answer given by the scientific literature. So, no, it is not a proof, but it is as close as we can get. – Zonata May 21 '13 at 5:16

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