Talk:Biology and sexual orientation/Archive 1

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Archive This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

I've added some more detail on the LeVay hypothalamus study, which seemed a little sketchily-described before. I hope I haven't made the description too long - if so, someone is welcome to shorten it. Given that this study has been subjected to constant methodological criticisms (try a Google search), it seemed reasonable to discuss some aspects of the methodology, particularly relating to the classification of subjects, in more detail. I've also added information on the similar, more recent study by William Byne and colleagues. I agree with the maveric149 that the current title of the article isn't perfect.

I will add some stuff on twin studies in a few days if I get the time. --EALacey, 14 June 2003

The twin studies section is done, though somebody might like to make it a little more concise if they think it's too long. EALacey 11:28 22 Jun 2003 (UTC)
Great work! --mav

removed from article:

These studies show that there is no scientific data to support a genetic or biologic basis for same-sex attractions.

This statement doesn't logically follow the findings of these studies; which have shown that 1) there is a possible sexual-orientation dimorphism (difference in the size of a part of the brain), 2) the sexual orientation of identical twins seems to follow a predictable pattern once the orientation of one twin is known, and 3) there is a cetain gene that tends to follow individuals who identify as homosexual. --maveric149

In addition, the current title of the article misses the point -- only one of these studies really deals with genetics. The other two deal with phenotypes and behavior -- which arise from varying degrees of interaction between genes, the chemical environment of the body, the outside environment, self-identification, etc. A MUCH better title would be innate basis of sexual orientation. If there is such a thing as a 'gay gene' (or more likely genes) there is every reason to believe that it/they has/have only some degree of influence on sexual orientation that is somehow "set" in early to late adolescence (thus its supposed "innateness"). Many other factors are probably also at play. --maveric149

I agree that the "no data to support" sentence was biased. Thank you for removing it. Readers should be free to draw their own conclusions.

I am open to an improved title, too. I only chose "genetic basis" because that's what the three types of studies seemed to be focusing on, and the words gene and genetic are fairly well-understood to our general readership. I am not sure what innate means.

I contributed the article to shed light on the moral debate over homesexuality by presenting scientific findings related to the contention that adults cannot change their sexual orientation from homosexual to heterosexual. Some (most?) arguments over morality hinge on the aspect of human volition. A person who doesn't realize what he is doing is wrong, or who "can't help it", is judged far more leniently than, say, a murderer in cold blood. Not to say that homosexuality is equivalent to murder, of course! Just that people are only judged on what they can do. A better example might be a vehicle collision. If you didn't see that other car running the red light, you aren't held responsible, whereas if you plainly say the blind person slowly jaywalking across your path in plenty of time to stop, it's a different matter.

I am trying hard to distinguish between advocacy (which I seem to slip into unbeknownst to my self) and providing relevant, useful NPOV articles. I look forward to receiving additional feedback from Maverick and Danny and SR and anyone else who has good ideas on how I can improve my contributions.

Ed Poor, Wednesday, May 8, 2002

It's been almost a year since I wrote this article. Would someone please finish it? At least the twin studies... --Uncle Ed 22:31 Feb 27, 2003 (UTC)

Maybe this research item will help:

Gay Gene Isolated, Ostracized

BALTIMORE—On Friday, scientists at Johns Hopkins University isolated the gene which causes homosexuality in human males, promptly separating it from normal, heterosexual genes. "I had suspected that gene was queer for a long time now. There was just something not quite right about it," team leader Dr. Norbert Reynolds said. "It's a good thing we isolated it—I wouldn't want that faggot-ass gene messing with the straight ones." Among the factors Reynolds cited as evidence of the gene's gayness were its pinkish hue, meticulously frilly perimeter, and faint but distinct perfume-like odor.

--Uncle Ed 21:38 Mar 4, 2003 (UTC)

Hm. I don't know if I should laugh my gay-ass ass off or be insulted. --mav 23:15 Mar 4, 2003 (UTC)
I vote for the first one, though you should promptly reattach it. Tuf-Kat
LOL - now that was unquestionably funny. :) --mav

All of this seems to beg the question of whether "homosexuality" is even well-defined, let alone genetically determined. Seems to me that a social construct that has, at most, about 35 years of existence in something like its current form and less than 150 years in any even vaguely resemblant form would not readily expected to be tied to genetics. For example, there is an enormous methodological problem in determining whether a particular person is homosexual. How? Self-description of identity? Self-description of behavior? Controlled study of reaction to images? Is a (behaviorally) bisexual person "homosexual" in this sense? (Thought experiment: was Oscar Wilde a homosexual? How about Virginia Woolf?)

As recently as the 1960s, there was a tendency to count only one partner in many actions we would now call "gay sex" as homosexual. "Trade" were not considered homosexual. In the Spanish-speaking world, much the same obtains even today: a macho guy who has sex with effeminate men is categorized very differently from those effeminate men. With different cultural categories, a biological determinist would go looking for a gene for a different social trait. Why should anyone reasonably expect that this sort of search is any better science than phrenology? Why not expect a gene for monosexuality vs. bisexuality, or for preferring to be on the top during sex? Answer: because they are not comparably important categories in our culture so we don't go looking for them.

I could probably go on at great length, but I hope I've already made myself clear without expanding this into an essay. -- Jmabel 07:49, 5 Feb 2004 (UTC)

It is a fallacy to say that just because something is not known of or defined that it does not exist (did most of the elements not exist before they were discovered?). It is also a fallacy to state that something exists just because something is known of or defined (do UFOs exist just because they are known of?). Just because homosexuals have only been out for the last three decades or so does not mean that homosexuality (not just homosexual acts) didn't exist before then (and vice versa).
My point is that only sociological and especially biological studies can determine whether or not homosexuality is a new phenomenon or something that has always been with us. Oh and biology and sociology do interact. So if there is such a thing as a genetic predisposition to homosexuality, one would expect to see this acted upon differently in different societies. For example, in many parts of the Mid-East being gay is a capital offense. Needless to say homosexuality is highly repressed in those situations and thus does not appear to exist except as rare abberations. Please don't let past repression of "homosexuals" give you the impression that homosexuality did not exist during far more oppressive times. Let the researchers find this out. --mav 08:39, 5 Feb 2004 (UTC)

Don't get me wrong, I'm sure that some in the past there were a certain number of individuals who conformed reasonably well to our current notion of homosexuality. I'm just saying that there is a long history of searching for, and even seeming to find, scientific evidence for contemporary social contracts. What I am saying is that no one is looking for a genetic predisposition to be "trade", or to be a bondage bottom, or to prefer to wear lavender, because they are not important social categories in our current society. All of these are equally real, or unreal. I view with enormous skepticism any science that claims to validate contemporary social categories. A century ago, scientists were busily validating racial categories that are almost all now considered as lacking scientific validity. -- Jmabel 21:38, 5 Feb 2004 (UTC)

? Different groups of people have different gene pools. Yes we are all remarkably alike for mammals, but there are regional variations (such as average height, skin color, pre-dispostion to certain ailments and abilities, etc.). Just because it is not PC to note these differences does not mean they do not exist (but all such claims need to be taken critically due to past abuse of those type of claims, of course). And please do not confuse 19th century eugenics, phrenology, and social Darwinism quacks with scientists. The comparison by example to current researchers is also a bit off. --mav

Remember that they were not considered quacks in their own time. Yes, different people have different gene pools. There is probably a reasonable biological definition of "Icelanders" or "Ashkenazi", one that would correspond (closely, though not perfectly) with the normal use of the terms. But consider (for example) that there is now known to be more genetic diversity within the "negroid" people than in the entire rest of the human species.

Would you agree that there is sociological rather than a scientific reason that contemporary scientists are looking for genetic "causes" of homosexuality rather than genetic "causes" of (exclusive) heterosexuality? If not, we are so far apart on this that I'll just drop the discussion with you and leave others to form their own conclusions. -- Jmabel 23:40, 5 Feb 2004 (UTC)

I agree but your question seems odd: The reason there is a genetic cause of heterosexuality is obvious; since we cannot reproduce asexually at least some men and women need to have sex to propagate the species. And there is a great deal of previous research on that subject and why sexual reproduction evolved in higher taxa and why it has persisted for so long. So some current researchers are investigating questions that do not have clear answers yet. But others continue work on refining answers as to why heterosexuality exists. Their work just doesn't grab headlines. --mav

Certainly. But reproducing doesn't make one a "heterosexual" or, as I remarked above, we'd have to call Oscar Wilde a heterosexual. Ditto Leonard Bernstein. A strong case could be made that heterosexuality, as we now know it, is as much a social construct as homosexuality, as we now know it. -- Jmabel 01:19, 6 Feb 2004 (UTC)

By "heterosexuality" I meant "sexual attraction primarily to the opposite sex". That is not a social construct. The reason this is useful in an evolutionary sense is that it encourages reproduction. --mav

Well, obviously. Trivially. But clearly, these studies don't directly study, say, "sexual attraction primarily to the same sex." "Attraction" is very hard to measure. At best they study patterns of actual behavior. At worst they study who-knows-what (e.g. as the article notes in passing, the criteria for the classification of gay and non-gay in LeVay's study seem a bit murky; I make that remark not on the basis of this article but of other things I have read about the study). -- Jmabel 08:59, 6 Feb 2004 (UTC)

Contents

homosexuality and natural selection question

I am curious to know if anyone has ever come across any information on the web concerning the genetic basis for homosexuality in light of the generally accepted theory of natural selection. I am writing a short paper on the subject and I am having trouble narrowing my internet searches sufficiently to uncover anything. Basically, my question is this: If a gene for homosexuality exists in the human genome, why has it not been "weeded out" after countless generations in which the most highly reproductive individuals would have been selected for? Obviously homosexuals would have passed on their genes far less frequently than heterosexuals, so how is it that these genes are still present in the human populations of today? Hopefully some of you will know a possible answer to this question or perhaps be able to suggest likely places on the web where I can seek it out myself. I appreciate your time in reading this message.

-Brook

I know the "kindly gay uncle" theory has been proposed, meaning that a family member who does not reproduce has the time and resources to help nieces and nephews out, thus propagating his family's genes. Sounds rather dodgy to me, but some people do or have accepted it. Tuf-Kat 18:29, Mar 12, 2004 (UTC)
It isn't at all obvious that gay and lesbian people would pass on their genes far less frequently considering the intense pressure to be straight and reproduce over the last few hundred years. Gay people pass on their genes all the time, in fact, gay and lesbian teenagers are twice as likely to impregnate someone or be impregnated (http://www.lesbianinformationservice.org/pregnancy.rtf). See: situational sexual behaviour and causes of sexual orientation. Hyacinth 17:07, 7 Apr 2004 (UTC)

Yes but there is no pressure on animals yet they also show homosexuality. Also a few hundred or even thousand years in nothing in evolutionary terms.

jucifer 19:08, 23 Nov 2004 (UTC)

Points taken. However, even without those specific extraordinary pressure(s), gay people are capable of reproduction. Hyacinth 01:09, 24 Nov 2004 (UTC)

Okay, I guess I am someone new to this whole organization, but the most common, and least partisan view that I have found is the idea of "'predisposition'", or increased risk of development through a trait rather than a guaranteed inheritance, it means that people could carry the gene, but never develop homosexual tendencies nor realize that they had the potential to actually be homosexual. Also, it could explain bisexuality, its great prevalence, and how so many people are not pure in their inclined feelings and/or behavior throughout their lives. So for whomever it is who is asking about the "homosexual gene'" may ""predisposition"" possibly serve as a helpful keyword to you.

Also, in the primitve sense(before assistive reproductive technologies), not all people who label themselves "'homosexuals'" only sexually interact with the same sex. There is a difference between taking on an identity as homosexual and being exclusive in sexual behavior, in fact many people in the population are actually bisexual, and not exclusively homosexual.

-Morpheus 2004

What the studies show

Cut from article:

These studies lend credence to the idea that there is a genetic component to sexual orientation, or that homosexuality and heterosexuality may be partly the result of some otherwise innate physical characteristic(s).

Actually, this is exactly the opposite of what the studies show. They take away credence from the idea that there is a genetic component to sexual orientation; they don't bolster it at all.

Unscrupulous or careless journalists may have cited these studies, or used selective quotation to make it seem like the studies provided evidence for the "gays are born that way" hypothesis.

But the researchers themselves say that such a conclusion is a misrepresentation. --Uncle Ed 17:19, 6 Apr 2004 (UTC)

From the article:

These are theories: hard empirical data is lacking

Shouldn't this be "These are hypotheses"? This article is mostly scientific, and as such should use the scientific definitions of theory/hypothesis, not the popular ones. CyborgTosser 01:42, 13 May 2004 (UTC)

Well, if there's no argument... CyborgTosser 17:54, 28 May 2004 (UTC)

This article is solely devoted to humans. I know a lot of observation has been done on homosexual behaviour in animals, but has any of it been researched in the context of genetics? If so it would make a useful addition to this article. Pcb21| Pete 01:13, 30 Aug 2004 (UTC)

subject -> participant

Apologies to all for the mistaken replacement of 'subject' to 'participant'. Thanks to User:Jmabel for correcting it.

I was replacing 'subjects' with 'participants' in several articles to make them comply with modern thinking and psychology guidelines. The term 'participant' is now commonly regarded as more appropriate than 'subject' when referring to humans that consent to take part in experiments. I was skim reading the articles and did not notice that the humans in the experiments this article were dead. If I had noticed that, I would have left the terms as they were.

In case anyone is interested, examples of the psychology guidelines that mention the use of terms like 'subject' and 'participant' include:

Bobblewik  (talk) 09:10, 12 Sep 2004 (UTC)

Argument against a genetic cause

The quote below was added near the top of the article at 05:25, 10 Apr 2004 by 130.235.172.210.

A strong argument against a genetic cause, however, is that such genetic variations, which disfavour reproduction in a species would hardly survive a few generations.

I am surprised it has lasted this long unchallenged. It is POV, unscientific (using a similar argument you would expect that we would have no lasting genetic disorders that led to death in childhood) and definitely out of place given that this argument is largely discussed in the conclusions of Twin studies.

Any genetic component must be rooted in evolution by natural selection, and many non-scientists assume that a homosexual orientation would necessarily result in decreased reproduction [my bolding]. Gene prevalence, however, and therefore selection, can be influenced by increasing the reproductive success of individuals with whom we share genes in common. While it may be unclear to some how homosexuality could offer a selective advantage to individuals, many hypotheses exist that explain why an inherited tendency toward this orientation might offer a selective advantage to the genes they carry. Most hypotheses speculate that the presence of homosexual members may also promote intragroup harmony. These are hypotheses: hard empirical data is lacking. Apparent homosexual behavior provides a stealth mechanism for slipping past alpha males in some species; like most putative explanations, that does not explain inheritance of female homosexuality. Some twin effects could be the result of their shared environment from conception to birth.

My view would be to simply delete it. Any comments? --CloudSurfer 07:32, 27 Sep 2004 (UTC)

I think it's worth (1) keeping this (or something like it), preferably with a citation of someone making this case, (2) characterizing it as a naive objection, and (3) laying out the case, also with citation, for the possible evolutionary value of the "gay uncle". - Jmabel 17:23, Sep 27, 2004 (UTC)
My point is that this view is already discussed without citations in the conclusions to the twin studies where it is characterised as coming from "non-scientists". I believe it should be taken out of the lead paragraphs as it is unbalanced in that context and thus misleading. Perhaps the view in the "twin conclusions" could be put with more force. e.g.
Any genetic component must be rooted in evolution by natural selection, and many non-scientists assume that a homosexual orientation would necessarily result in decreased reproduction and would thus die out over several generations. ...
--CloudSurfer 18:38, 27 Sep 2004 (UTC)

Homosexuality as decoy theory

So, I was bold.

I did not address this theory, though:

Apparent homosexual behavior provides a stealth mechanism for slipping past alpha males in some species; like most putative explanations, that does not explain inheritance of female homosexuality.

You might argue that the ability to appear non-competitive to members of the same gender gives advantage, whether male or female. Personally, I find this theory a little badly formed, because it seems more like an evolutionary theory in support of bisexuality, but not purely homosexual attraction, per se. Except perhaps as an maladaptive side-effect. But that doesn't mean that the pros and cons of this idea shouldn't be included in the article. But I'm not sure I have a clear grasp of what people who believe in this theory actually are advocating. Perhaps someone else is more familiary with the theory or there is documentation of the ideas of a popular advocate?

-- Beland 03:18, 28 Sep 2004 (UTC)

Bisexuality and evolution

I mostly agree with this except: "If heterosexuals have an individual reproductive advantage over homosexuals and bisexuals..." Why on earth would being bisexual be any reproductive disadvantage? -- Jmabel 05:22, Sep 28, 2004 (UTC)

With a given sex drive, a finite lifetime, and a given population of potential mates and competitors, bisexual creatures would "waste" certain mating opportunities by choosing members of their own gender. (How often that happens depends on the frequency of same-sex choice of mate, and the effects of non-cooperation from heterosexual same-sex partners, probably among other factors.) Over a long period of time, this should result in the heterosexual creatures out-breeding them, all else being equal. -- Beland 06:44, 28 Sep 2004 (UTC)
I think that's just silly. What matters for reproductive purposes is how much one breeds with fertile individuals of the opposite sex, not how little other sex one has. By your logic, masturbation would be a reproductive disadvantage, too. -- Jmabel 06:58, Sep 28, 2004 (UTC)
In the developed world couples seem to be producing approximately two children per mating pair, give or take minor variances. What is all this nonsense about? Evolution seems to be severely challenged by conscious choice. The vast majority of sexual endeavours end with fun, not fecundity. --CloudSurfer 08:19, 28 Sep 2004 (UTC)

Well, the modern developed world has only existed for a few hundred years, and civilization itself for only a few tens of thousands of years. These are very short periods of time, evolutionarily speaking. The genetic composition of the human race as a whole has not really changed very much since the rise of civilization. So if we are interested in the genetic factors that shape sexual attraction and behavior, then we need to look at evolutionary conditions over the past hundreds of thousands or millions of years.

But it is true that the world has changed a lot since those pre-historic days, and of course putting the same genome in a markedly different environment is going to produce different results.

And of course you are right that conscious choice affects reproduction. Moveover, many evolutionary mechanisms that have been at work for billions of years have in modern times been trumped by human technology and intelligence. But the question we are trying to answer here is not where we will be in million years from now, but how we've gotten to the point we're at now (and more particularly what internal mechanisms we've inherited from the past and how they interact with the modern environment). -- Beland 23:50, 29 Sep 2004 (UTC)

>>What matters for reproductive purposes is how much one breeds with fertile individuals of the opposite sex, not how little other sex one has.<<

Of course. So if we have a bunch of genes that end up causing an organism to have sex with same-sex partners without reducing their mating activities with opposite-sex partners, assuming there are no child-care or survival-rate penalties from any additional time and energy spent doing that, there's no reproductive disadvantage. If, on the other hand, the number of opposite-sex partners or mating events is reduced as a result of partial same-sex attraction, then there will almost certainly be some reproductive disadvantage unless other factors intervene to prevent that from having an impact on number of offspring vs. heterosexual competitors. How the actual genes that actual human bisexuals have inherited which may or may not have some influence on their attraction and behavior are supposed to fit into this picture, is entirely unclear. Which is covered in more detail, I hope, in the discussion on adaptiveness in the article. -- Beland 23:50, 29 Sep 2004 (UTC)

Firstly my apologies for using the word "nonsense" which was inappropriate and I thank the anonymous writer for their calm and reasoned response. It should be apparent to anyone who observes animals that mounting behaviour has a percentage of same sex couplings. From my limited personal experience this is true for dogs and cows and I have not personally observed it in other species although I believe there is a literature on this. For instance, I understand that dolphin males at times group in pods and appear to rape other males. So far I have mentioned only social animals and it may well be that there are still "nurture" factors in these despite the apparent lack of language (with the exception of dolphins). The problem is that there is a significant push in the human debate to deny a genetic cause for dogmatic rather than logical reasons and this is what "heated" my response. Again my apologies. --CloudSurfer 05:31, 30 Sep 2004 (UTC)
Oh, that was me accidentally mangling my signature (since fixed). "Nurture" is such a broad term, it's often used to include things like environmental conditions and even things like fetal hormone exposure. Personally, I don't think the world divides up neatly into these two camps, and discussing real-world causes rather than obsessing over how those causes are classified is probably more useful. But, hey, that's what people seem to like to do. -- Beland 01:41, 2 Oct 2004 (UTC)

Reorganization

I got a personal request to fix the intro section so that it's no more than three paragraphs or so, to keep the TOC near the top. So I refactored the intro and headerized. Following the general rule of putting layperson-accessible content first in scientific articles, I moved the Politics section up. I also moved the "Twin studies" section up, because this type of study seems to most directly address the question at hand. -- Beland 00:11, 30 Sep 2004 (UTC)

New study

Reported by the BBC today here - http://news.bbc.co.uk/2/hi/health/3735668.stm - may be of interest to the keepers of this article. Pcb21| Pete 08:09, 13 Oct 2004 (UTC)

Now integrated into the article. Thanks for pointing this out! -- Beland 06:21, 11 Apr 2005 (UTC)

Disputed

The material in this section appears to be taken largely from a report similar to [1] or perhaps this same one. The current Wikipedia text seems to summarize the BBC report incorrectly in that it conflates two different scientific theories. I will attempt to fix it. -- Beland 05:40, 11 Apr 2005 (UTC)

OK, this section now accurately represents my understanding of what the BBC was reporting. It would be very worthwhile to dig up the original studies to make sure what we are reporting accurately represents what the journal articles said. -- Beland 06:20, 11 Apr 2005 (UTC)

HIV/AIDS and brain features

Also, HIV/AIDS may affect the brain, causing chemical changes. So rather than showing that differences in neurons indicate homosexuality, LeVay's study may be showing that HIV/AIDS causes differences in neurons. It should be noted, however, that neither LeVay nor Byne found an HIV-related difference in INAH3 size.

I'm wondering whether or not this is a spurious and/or misleading statement. Did LeVay actually check for this? Is this a plausible confounding variable proposed in a scientific journal article, or is this something a random Wikipedian thought up? -- Beland 06:34, 11 Apr 2005 (UTC)

This is roughly what LeVay said. He's stated many times that his study proves (though it also doesn't disprove) no correlation between homosexuality and brain structures - there were just too many uncontrolled variables. -Seth Mahoney 18:37, Apr 11, 2005 (UTC)

Darwinism

I found this in the "Homosexuality" article:

Georgetown University explaining the widespread homosexuality and attractions in adolescence has theorized this may be an integral part of bonding to reduce inter-species aggression later in life when many become bisexual.

I couldn't find any more information about this through a quick Google search. It sounds like a dubious theory, but is very likely being misreported here, so I'm removing it until more research on the subject can be done. -- Beland 04:08, 5 May 2005 (UTC)

I think that is there dolphin theory. That is a good question. Should this article also cover sexual orientation in other species? :) Polisci 03:25, 15 August 2005 (UTC)

Pheromones correlation

This section has no citation, and all significant content was anonymously added. Unless there is a citation, I am inclined to remove it: I see no way to identify the study in question, let alone clarify (for example) its methodology for identifying a person as heterosexual or gay. -- Jmabel | Talk 05:12, May 12, 2005 (UTC)

Oops! You caught me. I accidentally deleted the citation when I edited the content to avoid using a direct quote from the aritcle. -Seth Mahoney 02:32, May 13, 2005 (UTC)
I've now added the citation at the bottom of the article, along with the others. -- Jmabel | Talk 01:34, May 14, 2005 (UTC)