Science And Homosexuality

[LosingMyReligion]

Is there an evolutionary purpose for homosexuality?

 

I was always taught it was just a sin and unnatural...But since I've been cured of fundamentalist Christianity I'd like to know why does it occur...How does it occur, in males and females...

 

And why do practically all the animal species(including humans)participate in it.

[dibby]

Is there an evolutionary purpose for homosexuality?

 

I was always taught it was just a sin and unnatural...But since I've been cured of fundamentalist Christianity I'd like to know why does it occur...How does it occur, in males and females...

 

And why do practically all the animal species(including humans)participate in it.

 

Just something I heard once. At a critical phase of pregnancy if the mother has alot of stress hormones in the body at a critical stage of foetal development, then the foetus may develop a homosexual orientation. There could however be a genetic component that could increase the chances of this happening. It maybe more than one factor involved, the verdict is still out. Speculation: an evolutionary adaptation to an increasing population? More people crowded together, therefore more stress?

 

It is not however a simple lifestyle "choice" as the fundies say.

[Taphophilia]

Homosexuals still reproduce in all species, even humans, and pass down their genes.

 

It's just that humans don't have an estrus cycle anymore and it's not instinctual to procreate. I believe homosexuality like any sexuality developing without an esterus cycle is due to humans being social animals and the need for other human contact that we has evolved in us.

 

Taph

[LosingMyReligion]

A few nights ago I was watching this piece on 60 minutes about Gay genes.

 

To make a long story short one scientist said The more older brothers the youngest male child has the more likely he is to be gay.

That struck a chord with me. I am the youngest of five boys and I'm as queer as a three dollar bill.

It also said(and it is an extension of the former theory)that gay men get a bit more estrogen than straight men...So does that mean that lesbians have more testosterone?

[Taphophilia]

I personally think (wouldn't surprise me if I'm wrong) that homosexuality, transgender, bi-sexuality is connected to the fact that we all start out female in utero.

 

Personally, I don't understand what the big deal is. Sexuality is such a small part of who we are, who cares who you are attracted to. Why are Christians so damn concerned about who is having sex and with whom?

 

Taph

[Guest Tiffany]

we all start out female in utero.

 

As a transgendered male this explanation sounds the best... I start out as a female, nature try's to make me into a male but can't complete the process so I end up a hybrid.....

 

Actually that kinda makes the GLBT crowd sound like defects, Yippee! I'm defective! lol

 

I can't say what it is that makes us GLBT but I hope were not natures accidents.

 

 

 

 

I feel like an X-Man, a girl with the power to transform into a man... only problem is I can't change back.

[Zach]

Biological homosexuality was always seen as a kind of perfect rebuttal against evolutionary theory- if evolution is driven by organisms passing on their genes, how does homosexual behavior continue to manifest?

 

There has been some evidence recently to show that there may be, in fact, biological causes for homosexuality- male homosexuality, to be specific. Genetic linkage studies have shown a strong correlation between homosexuality and the X chromosome- the only chromosome that, in men, is inherited solely from the mother. Efforts to single out specific genes on that chromosome have been unfruitful thus far, but are ongoing. There is also evidence to suggest that birth order plays a role- specifically, the more older brothers one has, the more likely one is to be homosexual.

 

Although blaming your mother for your gayness may seem attractive, still the question is, "why does homosexuality stick around given evolution?"

 

In the case of the X-chromosome linkage studies, it has also been observed that females who tended to share X-chromosomes with homosexual male relatives also tended to have more children overall. Whether any putative "gay gene" might also be a "mother gene" is unknown, but the evolutionary tradeoff is obvious- any given female gains more in evolutionary advantage by having more children then she loses by having homosexual male relatives, particularly because her male relatives aren't potential mates anyway.

 

In the case of the fraternal birth order, it's been suggested that repeated exposure to male antigens may generate maternal antibodies that suppress developmental pathways necessary for heterosexual neurological conditioning. This may not be evolutionarily advantageous, but it is unlikely to be disadvantageous either, since males have a much longer period of reproductive potency compared to females.

 

Homosexuality is also extremely common in other animal species. Usually, it's seen in situations where individual males mate with a large number of females, leaving nothing for the other males but to satisfy their instincts with each other. This would technically be functional bisexuality- I've not read many reports of individual animals preferring homosexual relationships over heterosexual relationships, but they may certainly exist.

 

we all start out female in utero.

That's not technically accurate. As fetuses, we have both proto-female and proto-male organs. Our external genitals are an approximate intermediate of both female and male genitals, but since male genitals are much more pronounced, it appears to be more female than male. If the fetus is female, the genitals become a distinct vagina, and in males they become a distinct penis and scrotum. In both, the internal ductwork of the opposite sex dissolves away.

 

This is why hermaphrodites exist- sometimes the choice isn't made clear, and both sets of genitals develop.

[JGJ@ReligionisBullshit]

It cannot be a DNA/RNA disorder by evolution, homosexuality cannot be passed down as a genetic trait unless a homosexual ancestor reproduced at some point and passed the defective portion. I agree with others above, must be hormonal and the more the older brothers you have the more chance you have of depleting the mother's supply of the testosterone before it can be replenished, especially if they are born relatively close together. But I'm just guessing, Genetics isn't for a couple more weeks in my A&P, have to cut the piglet up first.

[Lycorth]

I think it could be hormonal, too, but then again, I'm not a biologist - hence, what do I know?

 

All I know that a human being is a human being and should be treated as a monster only if monstrous behavior is willfully exhibited. Since deconverting, homosexuality no longer seems like a big deal to me, because I see that it really doesn't adversely affect a person's capability to make positive ethical choices. That said, I agree with Taphie, and don't think it's a problem in the slightest.

[Zach]

Actually that kinda makes the GLBT crowd sound like defects, Yippee! I'm defective! lol

 

I can't say what it is that makes us GLBT but I hope were not natures accidents.

I do want to point out that "normal" is not a biologically meaningful concept. Homosexuality may be a minority behavior, but that does NOT mean that homosexuals (or transgenders, or intrasexuals, etc.) are "defective." If there's anything at all that biology is teaching us as we learn about the genetics of humanity, it's that there's a wide array of variation at ALL levels. To single out an individual's sexual preference as the only aspect to determine "normality" seems arbitrary at best and downright silly at worst. By the same criteria, redheads are genetically "defective". In fact, every individual is born with an average of 175 "defects" in the form of mutations. Science is complcated enough without inserting morally loaded concepts into it.

 

Rant over.

[Thurisaz]

Biological homosexuality was always seen as a kind of perfect rebuttal against evolutionary theory- if evolution is driven by organisms passing on their genes, how does homosexual behavior continue to manifest?

 

I never could help myself but laugh when I encountered this "reasoning". Who the fuck (except fundie numbnuts of course) said that homosexuality, inasmuch as it is genetic, is 1. dependant on one single gene and 2. an all-or-nothing affair (either 100 % hetero or 100 % homo)?

Let's assume that there are about 50 genes contributing to homosexuality, and that if you cross the threshold of 30 genes you become a homo. Imagine that your mom has some 20 genes, not enough to make here homo. Your dad has another 20 of them, partially overlapping with those of your mom. And you happen to have a total of 32 "homo genes" as a result of the genetic mix. Presto, perfect explanation for homosexuals still contributing to reproduction - only the people where it "breaks out", so to say, may stop pumping them back into the gene pool.

Let alone that first there's bisexuals too, and of course bigotry contributes its share to a number of homosexuals playing hetero including having opposite-sex partners.

 

Yeah right, it's such a puzzle.

 

I think it could be hormonal, too, but then again, I'm not a biologist - hence, what do I know?

 

You know, just yesterday when I was idle at work I read through part of the index of cretinist claims again, and I encountered the current state-of-the-art of explaining homosexuality in the context of science. It's pretty much a combination of everything said here so far.

[JGJ@ReligionisBullshit]

Well, I guess we athiests are as stupid as some Xtians claim. Ha!

[spamandham]

Is there an evolutionary purpose for homosexuality?

 

No one knows. It might have an evolutionary benefit by producing a male who can help the tribe collect food without adding the burden of his own offspring, or it might not.

 

It's also possible that homosexuality just happens randomly and serves no evolutionary purpose, but rather, is a side effect of having two sexes.

 

That said, we are not slaves to evolution. Do whatever fulfills you without concern about how the gene pool plays out. Why the fuck should we care if our genes have not programmed us to care?

[Guest Tiffany]

Getting back to the evolutionary purpose of homosexuality I'm beginning to get depressed here....

 

After reading all the posts above I can only conclude that atheists believe all GLBT people (Gay, Lesbian, Bisexual, Transgendered) to be mistakes, oopses, accidents of evolution... the remainder in an otherwise perfectly independent system.

 

Do we have no evolutionary purpose?

 

Are we natures mistakes on the road to create the perfect heterosexual?

 

Why don't I just off myself and do my part to cure this ailment that threatens our precious heterosexual population?

 

 

 

 

 

You know me... Drama queen! please don't take offense.

[♦ ficino ♦]

A study a while back found that one of the anterior lobes of the hypothalamus is four times as large in heterosexual males as it is in females and gay males. I think the sample in the study was small. Still, I've seen it cited in responsible books about adolescent psychology as though it is a valid study. I think the conclusion the researcher drew was that gay men have different mixes of hormones from straight men, while admitting that there is a big range between these groups, with overlap.

 

Anyone more up to date on this than I?

 

Homosexual behavior in other species isn't rare. Bonobo chimps are famous for it as part of the behaviors that cement relationships within their society, especially among females.

 

Many homosexuals throughout history have had children. I think it's mainly since the mid nineteenth century that "homosexual" has been defined as a category rather than "sodomite" or some other category that defines itself by acts rather than inner nature. So maybe the question is more, why do gay men and lesbians so often not have children? Seems in recent years they're starting too, though, more and more.

[JGJ@ReligionisBullshit]

Like I said, it can't be evolutionary since it is not controlled by genes. At least I'm willing to go out on a limb and say that there is no gay gene and neither is it choice (well, not choice in most cases).

 

With that being said first let me say that I'm not a doctor nor am I an embryologist. I am a student in a medical field but I don't know everything. But I have enough knowledge of how the body works to make a pretty good guess. First, look at the roles of estrogen release, regarding sex, during pregnancy.

 

The two most important to this topic are:

1. It triggers the reproductive organs of the fetus to mature.

2. It regulates the the release and effects of other hormones like androgen.

 

As some of you may know, androgen is a steroid which is produced by the adrenal glands which sit on top of the kidneys, the ovaries, and the testes in different forms. Males and females both make androgen naturally. It stimulates the gonads to become male testes instead of female ovaries. It also plays a role in determining if the fetus will be more masculine of feminine by the amount released and accepted by the fetus. It is at this stage where birth defects such as Ambiguous Genetalia which is also called atypical genitalia can begin to occur and is a direct result of the sensitivity of the fetus to androgen that makes this happen. There are several atypical affects that can occur due to the sensitivity of the fetus, and even the mother, to androgen. Testes might not descend and the baby has ovaries and a something that looks like a penis, they could have testes and ovaries, or they could have no male or female descernable sexual organs, and even the mother can become more masculine after pregnancy. These are the extreme cases. Now let's look at the possiblilities of not extreme cases but a milder ones.

 

As we all have heard, steroids, including androgen, have a masculizing effect on the body. And as I have said above, the amount or strength of androgen that effects the fetus is regulated by estrogen that the mother releases during pregnancy. Let us create a hypothesis. The fetus is male, it was chosen by the xy chromosones. The estrogen of the mother is weak enough to allow the gonads to become normal male reproductive organs and yet not powerful enough to regulate the androgen at certain stages or in specific areas of the developing brain to make the future child very masculine, so the estrogen makes the child more feminine. You could have a wide variation of these effects from flaming homo to a guy that cries at movies, even make them more susceptable to depression, the types of food they eat, whether they like sports, and so on. It inhibits the fetus' ability to produce enough testosterone by its feminizing effects later in life to become the typical male. In a female child it could, very well, determine the size of the woman's clitoris (the woman's head of a male penis). They come in all sizes in case you didn't notice. Too much androgen sensitivity and you have a female who is interested in other females, only likes other females or even the "tomboy" syndrome.

 

There is also the possibility that the chromosomes involved have defects in the genes and that these are passed on. I highly doubt that this is an evolutionary response since it does not likely that the male will reproduce and pass this along. Since sexual characteristics are produced by two separate mechanisms, the type of chromosomes received and the sensitivity to androgen, I find it more likely that evolution is not involved at all. But this is all pure speculation on my part and I am just tossing it out there. Like I said before, when I get to the reproductive section, genetics, and embryology of my Anatomy and Physiolgy class next month; I will probably know more and perhaps change my mind.

[Shadoe]

After reading all the posts above I can only conclude that atheists believe all GLBT people (Gay, Lesbian, Bisexual, Transgendered) to be mistakes, oopses, accidents of evolution... the remainder in an otherwise perfectly independent system.

 

Do we have no evolutionary purpose?

 

Are we natures mistakes on the road to create the perfect heterosexual?

 

Well, I don't know about that. But I did read a report several years ago that claimed that homosexual behavior in animals that exhibited it did tend to increase at times when the population of that species had become too large to be supported by the environment. So maybe homosexuality is sort of a natural form of birth control.

[JGJ@ReligionisBullshit]

For Ficino,

 

As far as the hypothalamus goes, it does regulate the release of all exocrine hormones so it is possible that the size differentation is caused by having both a normal testosterone releasing center and one that controls the release of estrogen. Otherwise I would need to know more about that study. Have a link?

 

For spamandham,

I disagree, I think we are slaves to evolution. Otherwise we might be still walking on all fours. But that is neither here nor there if you don't hold to the theory at all. And I fail to see how having another food gatherer would benefit a society since males have always been in more demand for their hunting. Hunting is more dangerous and entails much more risk to the male, so the more males you have, the safer it is for everyone. Besides, the elderly and injured males who are unable to hunt can assist in the gathering portion without the need for some androgenous male running around making sure everyone was color coordinated in their furs.

 

For Tiffany,

I think the heterosexual human population is large enough that the heterosexual community has nothing to fear from homosexuality except on religious grounds. No need to off yourself, in fact, I can see the logic behind offing some of those who just can't accept anything done by others if it goes against some kind of theological belief. Get rid of religion and you can get rid of a lot of homophobia.

[Zach]

Getting back to the evolutionary purpose of homosexuality I'm beginning to get depressed here....

 

After reading all the posts above I can only conclude that atheists believe all GLBT people (Gay, Lesbian, Bisexual, Transgendered) to be mistakes, oopses, accidents of evolution... the remainder in an otherwise perfectly independent system.

 

Do we have no evolutionary purpose?

 

Are we natures mistakes on the road to create the perfect heterosexual?

 

Why don't I just off myself and do my part to cure this ailment that threatens our precious heterosexual population?

 

 

 

 

 

You know me... Drama queen! please don't take offense.

 

Is anyone reading my posts? I just explained this above.

[JGJ@ReligionisBullshit]

I read it Zach, but can't accept it wholly but only in part, read my post above, the long one.

[♦ ficino ♦]

Here's one of several links about brain, hormones and sexual differentiation:

 

http://brainmind.com/Hypothalamus.html

 

Rhawn Joseph's link refers to two studies about the smaller anterior lobe of the hypothalamus in women and gay men compared to heterosexual men. The first researcher to go into this was Simon LeVay, mentioned in Joseph.

 

See also this good link by Renato Sabbatini:

 

http://www.cerebromente.org.br/n11/mente/e...bro-homens.html

 

Sabbatini refers to Levay's original research and to Levay's 1994 book called The Sexual Brain (MIT Press).

 

 

JGJ, you said you didn't think sexual orientation is genetically determined but rather is partly caused by chemicals from the mother, to which the developing fetus is subject. If you take a step back, though, isn't this a way of saying that sexual orientation is in fact at least partly genetically determined? It's genetic in that human fetuses are susceptible to the womb influences you speak of, and it's genetic in that human females have the capacity to produce the chemicals that influence homosexuality (or what we now label as such) in their offspring. Some mothers must have that capacity more than others, which the layman would think is likely a function of those women's own genetic makeup. So the capacity for a range of "orientations" does lie within the genetic mix of the human species as a whole, does it not?

[JGJ@ReligionisBullshit]

Here's one of several links about brain, hormones and sexual differentiation:

 

http://brainmind.com/Hypothalamus.html

 

Rhawn Joseph's link refers to two studies about the smaller anterior lobe of the hypothalamus in women and gay men compared to heterosexual men. The first researcher to go into this was Simon LeVay, mentioned in Joseph.

 

See also this good link by Renato Sabbatini:

 

http://www.cerebromente.org.br/n11/mente/e...bro-homens.html

 

Sabbatini refers to Levay's original research and to Levay's 1994 book called The Sexual Brain (MIT Press).

 

 

JGJ, you said you didn't think sexual orientation is genetically determined but rather is partly caused by chemicals from the mother, to which the developing fetus is subject. If you take a step back, though, isn't this a way of saying that sexual orientation is in fact at least partly genetically determined? It's genetic in that human fetuses are susceptible to the womb influences you speak of, and it's genetic in that human females have the capacity to produce the chemicals that influence homosexuality (or what we now label as such) in their offspring. Some mothers must have that capacity more than others, which the layman would think is likely a function of those women's own genetic makeup. So the capacity for a range of "orientations" does lie within the genetic mix of the human species as a whole, does it not?

 

 

It's a good point but I'm not sure if the susceptibility is caused by genetics or the placement of the egg in the womb and subsequently the developing fetus, how androgen is introduced to the fetus, or any other of a number of factors when you step back further. I don't think enough is known yet to make a true determination, especially by myself and I just consider myself an informed layman. I can at least read medical texts and understand what they are saying.

 

It is quite possible that if there is a gene that determines a body's level of involvement with androgen and other steroids since reactions from oral usage of steroids like prednizone can vary from person to person. Do I think it is possible? Definitely yes! Do I think it is necessary? Not really. Hormones do not affect genes or genetic makeup but can alter the results of genes that have already run through their instructions. Take a simple thing like voice production for an example. The genes gave the instructions for creating the size, shape, and function of the vocal cords but hormones can deepen a voice. There are several examples of how hormones can alter our person both mind and body. Testosterone therapy for males produced results that were unforeseen. Hormone therapy is rather new and still well within developmental and experimental stages. I believe that once we learn more about hormones and their affects at different stages of development we will know more about things that we didn't even consider to be influenced by hormones before, such as cancer treatments, allergies, even homosexuality.

 

I just read your link for http://brainmind.com/Hypothalamus.html and am glad to see that what I said in the above post is in agreement with what I proposed.

 

"For example, if the testes are removed prior to differentiation, or if a chemical blocker of testosterone is administered thus preventing this hormone from reaching target cells in the limbic system, not only does the female pattern of neuronal development occur, but males so treated behave and process information in a manner similiar to females (e.g., Joseph et al. 1978); i.e. they develop female brains and think and behave in a manner similar to females. Conversely, if females are administered testosterone during this critical period, the male pattern of differentiation and behavior results (see Gerall et al. 1992 for review)."

 

I did not specify testosterone, but testosterone is an androgen.

[♦ ficino ♦]

 

 

 

JGJ, you said you didn't think sexual orientation is genetically determined but rather is partly caused by chemicals from the mother, to which the developing fetus is subject. If you take a step back, though, isn't this a way of saying that sexual orientation is in fact at least partly genetically determined? It's genetic in that human fetuses are susceptible to the womb influences you speak of, and it's genetic in that human females have the capacity to produce the chemicals that influence homosexuality (or what we now label as such) in their offspring. Some mothers must have that capacity more than others, which the layman would think is likely a function of those women's own genetic makeup. So the capacity for a range of "orientations" does lie within the genetic mix of the human species as a whole, does it not?

 

 

It's a good point but I'm not sure if the susceptibility is caused by genetics or the placement of the egg in the womb and subsequently the developing fetus, how androgen is introduced to the fetus, or any other of a number of factors when you step back further. I don't think enough is known yet to make a true determination, especially by myself and I just consider myself an informed layman. I can at least read medical texts and understand what they are saying.

 

It is quite possible that if there is a gene that determines a body's level of involvement with androgen and other steroids since reactions from oral usage of steroids like prednizone can vary from person to person. Do I think it is possible? Definitely yes! Do I think it is necessary? Not really. Hormones do not affect genes or genetic makeup but can alter the results of genes that have already run through their instructions. Take a simple thing like voice production for an example. The genes gave the instructions for creating the size, shape, and function of the vocal cords but hormones can deepen a voice. There are several examples of how hormones can alter our person both mind and body.

 

Hey JGJ, fascinating stuff, this, and way out of my area of specialty. I wonder whether you and I are just talking about genetic dispositions differently, i.e. you're being more narrow and precise in your use of technical terms than I am. If stuff happens in the womb to affect the fetus, it seems on some macro level that human genetic potential is a necessary precondition.

 

My thought is, gay-influencing hormonal affects on the fetus could be outcomes of trauma undergone by the pregnant mother, or they could result from that mother's normal hormonal balance. If they occur during a normal pregnancy, then can't we invoke the notion of genetic makeup insofar as some humans have them?

 

This all begs questions like, what's defined as normal vs. abnormal, what counts as trauma, etc. I think what is relevant for political and religious discussion of homosexuality is the point that the fetus can't choose its environment. So those factors of sexual orientation that are attributed to that environment cannot be rationally set to the gay or lesbian person's "blame" any more than they can to the "credit" of the heterosexual. Classical Judaism and its other monotheistic offshoots are in error ethically when they call for punishment of people who are the way they are largely because of how they were put together in the womb - whether or not those people's DNA displays an identifiable gay gene.

 

If we ever find an identifiable "hetero" gene, we'll crack open the problem, won't we?

 

Thanks for making me think

[JGJ@ReligionisBullshit]

My understanding is that although we have mapped the human genome, completed in 2003, we still don't know all the combination of proteins that make us who we are. There could very well be, and most likely is, a protein that regulates our susceptibility to certain hormones. We could all have the same susceptibility or it could vary in minute to great amounts each time it is transcribed to be produced. We just don't know. If the genetic makeup were near enough to be the same in almost everyone besides a complete screw up it would be entirely up to the hormonal conditions present in the womb. If it was way off in everyone then yes, I could see that it is entirely a genetic process and dependent upon genetic make-up alone. If we had an accurate representation of the percentage of true homosexuality, those who are homosexuality by birth rather than by choice, we could have a clearer understanding of whether this is some genetic change in the influence of hormones or other factors. We have no clear information by which to build a premise and like in the article that you referred to, we can only go by a certain set values which may or may not represent the homosexual population. The Petrie dish is contaminated with a mix of different levels of homosexuality and varying conditions during pregnancy. It could be dietary for all we know.

 

All I can truly say is that until we know how every chemical we breathe, ingest, or come in contact with affects a fetus we may never know. What we should do, in my editorial opinion, is accept people for who they are and not look for some mystical answer. You can't classify homosexuality as normal because it does not ensure the survival of the species. But then again, our species exists just fine and in greater number every year with homosexuality present so it certainly isn't a threat. Threats from homosexuality only come from a moral value sense that is different from person to person.

 

It is possible that someday we will know exactly what the causes of homosexual behavior are. And it is very likely that the very same day we do know, we will also be able to choose the traits of our children from eye color, food preference, and whether or not they like baseball to sewing. I think these things will happen simultaneously and one cannot happen without the other. So until that time, we should accept homosexuals like we accept those with dwarfism, spina bifida, and blonde hair and blue eyes.

[♦ ficino ♦]

There's also the sense in which, as social animals, our culture evolves along with us, since we produce it in big groups. Evolution of society is obviously a very vague topic. Still, I think a good argument can be made that gays and lesbians serve important communal needs and therefore further the interests of the species as a whole, or of groups within it, even if they turn out not to have children. It seems possible that Hebraic desert tribes benefitted less from homosexuality than, say, Greek city states, or city states in Palestine who had different social structures from the Hebrews.