The Science Of Sexual Orientation

[BabyBuddha]

I have copied some excerpts from the 60 Minutes transcript, that broadcasted Sunday March 12. It shows some very interesting information regarding sexual orientation. I think it is something that should be read especially by those that believe homosexuality is more nuture than nature.

Please read the entire transcript. (It was five pages and too long to post)


Psychologists used to believe homosexuality was caused by nurture — namely overbearing mothers and distant fathers — but that theory has been disproved. Today, scientists are looking at genes, environment, brain structure and hormones. There is one area of consensus: that homosexuality involves more than just sexual behavior; it’s physiological.


While biologists look at hormones for answers about human sexuality, other scientists are looking for patterns in statistics. And hard as this is to believe, they have found something they call "the older brother effect."

"The more older brothers a man has, the greater that man's chance of being gay," says Bailey.

Asked if that's true, Bailey says, "That is absolutely true."

If this comes as a shock to you, you’re not alone. But it turns out, it’s one of the most solid findings in this field, demonstrated in study after study.

And the numbers are significant: for every older brother a man has, his chances of being gay increase by one third. Older sisters make no difference, and there's no corresponding effect for lesbians. A first-born son has about a 2 percent chance of being gay, and the numbers rise from there. The theory is it happens in the womb.

 

[Guest]

Never though it was biological. Though it was due to the way the person thinks.

 

[ski2bfree]

It's about time this research has gotten some publicity. It's been well known in the scientific community for quite some time that sexual orientation relies heavily on genetics. I've actually witnessed my professor's work with this. She was able to isolate a homosexual strain of fruit flies by selective breeding. That's not to say that she bred the gay ones, because if they were gay they would not be breeding. She observed certain atypical behaviors and isolated the flies that exhibited them, then bred them. After a few generations, she found an entire colony of homosexual flies.

 

[Nightshade200]

I could have told you that. Its about time everyone else gets to see the facts as well.

 

[Guest]

I always said homosexuality was genetic. Alcoholism is as well!

 

[Nightshade200]

I can agree with the alchoholism bit as well.

 

[Guest]

Seem's many addictions are genetic.

 

[Lil'Jeffery34]

Never though it was biological. Though it was due to the way the person thinks.

Ditto.

 

[GoingNova]

It HAS NOT been proved that homosexuality is genetic. The following is from NARTH (National Association for Research & Therapy of Homosexuality). The bottom line is, as I have said many times in the past, there are doctors who believe you may be born gay, there are doctors who do not.

"Identical twins have identical genes. If homosexuality was a biological condition produced inescapably by the genes (e.g. eye color), then if one identical twin was homosexual, in 100% of the cases his brother would be too. But we know that only about 38% of the time is the identical twin brother homosexual. Genes are responsible for an indirect influence, but on average, they do not force people into homosexuality. This conclusion has been well known in the scientific community for a few decades (e.g. 6) but has not reached the general public. Indeed, the public increasingly believes the opposite.

Identical twins had essentially the same upbringing. Suppose homosexuality resulted from some interaction with parents that infallibly made children homosexual. Then if one twin was homosexual, the other would also always be homosexual. But as we saw above, if one is homosexual, the other is usually not. Family factors may be an influence, but on average do not compel people to be homosexual.

Twin studies suggest that as a class, events unique to each twin--neither genetic nor family influences--are more frequent than genetic influences or family influences. But many individual family factors (such as the distant father) are commoner than the individual unique factors. Unique events would include seduction, sexual abuse, chance sexual encounters, or particular reactions to sensitive events, when young. Everyone has their own unique path which only partly follows that of the theoreticians!

A fascinating sidelight on all this comes from the work of Bailey (7). His team asked non-concordant identical twins (one was homosexual, one not) about their early family environment, and found that the same family environment was experienced or perceived by the twins in quite different ways. These differences led later to homosexuality in one twin, but not in the other."

 

[Guest]

I can't beleive its biological, I think its due to the person and their environment. Things in their life cause them to go to homosexuality.

 

[smo1704]

Okay, there are three major theories regarding the nature of homosexuality:

1) It is genetic
2) It is based entirely on environment/personal choice
3) It is due to hormonal abnormalities during fetal development

#1 has been disproven by observation, as GoingNova has pointed out. Also, it is highly unlikely that a trait like homosexuality would survive evolutionarily (especially considering the number of species in which homosexual behavior has been observed), as it prevents those who express it from reproducing. Such traits, if they even survive, are generally far less prevalent than homosexuality.

#2 However, has also been disproven. Examinations of homosexual and heterosexual brains have shown substantial physical differences that cannot be accounted for by environment or choice.

#3 Has substantial empirical support. In experiments scientists have induced homosexuality by varying hormones during a key phase of fetal development. It would also explain why there are varying degrees of homosexuality, since the hormonal conditions would not have been the same from one individual to the next. Since individuals would have varying degrees of homosexual tendency as a result, you would have individuals for whom it was a choice (slight to moderate homosexual tendency) and those for which it was not a choice (severe homosexual tendency). It also explains why any male children after the first have an increased probability of homosexuality. Some of the hormones involved in male development are foreign to the mother's immune system, and after every male child the mother has a chance of developing an immune response to those hormones. Antibodies cross over from the mother's body into the fetus along with nutrients and oxygen. These antibodies can then interfere with normal male development by bonding with the necessary hormones and rendering them inert. This also explains why female children do not increase the chance of homosexuality, as none of the hormones involved in their development are foreign to the mother's immune system.

The fact that it has not been proven either way is irrelevant. In science nothing can be proven with absolute certainty. No matter how much evidence a theory accumulates it can never be declared “proven.†Some theories simply have much better empirical support than others. Based on the evidence I've seen, theory #3 matches observations far better than #1 or #2.

 

[GoingNova]

The fact that it has not been proven either way is irrelevant. In science nothing can be proven with absolute certainty. No matter how much evidence a theory accumulates it can never be declared “proven.†Some theories simply have much better empirical support than others. Based on the evidence I've seen, theory #3 matches observations far better than #1 or #2.

EXCELLENT post Smo! :applaus:

I think what bothers me the most though is when people (from either "side" of this argument) declare, with certainty, their position to be correct. You simply can not do that, particularly when one looks at the credentials of those who say you aren't born gay and the credentials of those who say you are. My point is, there are very intelligent people ON BOTH SIDES of this argument, and so neither side should present their position as an absolute.

 

[Guest]

Little in this world is absolute. I believe that one is born gay, however, I also believe in the theory that there is a range of latent to extreme homosexuality. Some people act upon their sexual preference and there are others who suppress it.

Since I believe there is a homosexual gene, I sometimes wonder if there is a possibility of a homophobic gene? The reason I have pondered this is because some people could care less if someone is gay while some people become unreasonable in their condemnation of ****.

 

[Guest]

Well I don't know if I can believe that its genetic, but I can agree that it can be something that happens during birth and due to the environment.

 

[ski2bfree]

It HAS NOT been proved that homosexuality is genetic. The following is from NARTH (National Association for Research & Therapy of Homosexuality). The bottom line is, as I have said many times in the past, there are doctors who believe you may be born gay, there are doctors who do not.

"Identical twins have identical genes. If homosexuality was a biological condition produced inescapably by the genes (e.g. eye color), then if one identical twin was homosexual, in 100% of the cases his brother would be too. But we know that only about 38% of the time is the identical twin brother homosexual. Genes are responsible for an indirect influence, but on average, they do not force people into homosexuality. This conclusion has been well known in the scientific community for a few decades (e.g. 6) but has not reached the general public. Indeed, the public increasingly believes the opposite.

Identical twins had essentially the same upbringing. Suppose homosexuality resulted from some interaction with parents that infallibly made children homosexual. Then if one twin was homosexual, the other would also always be homosexual. But as we saw above, if one is homosexual, the other is usually not. Family factors may be an influence, but on average do not compel people to be homosexual.

Twin studies suggest that as a class, events unique to each twin--neither genetic nor family influences--are more frequent than genetic influences or family influences. But many individual family factors (such as the distant father) are commoner than the individual unique factors. Unique events would include seduction, sexual abuse, chance sexual encounters, or particular reactions to sensitive events, when young. Everyone has their own unique path which only partly follows that of the theoreticians!

A fascinating sidelight on all this comes from the work of Bailey (7). His team asked non-concordant identical twins (one was homosexual, one not) about their early family environment, and found that the same family environment was experienced or perceived by the twins in quite different ways. These differences led later to homosexuality in one twin, but not in the other."

If I were you, I'd be a little skeptical about anything that NARTH has to say about homosexual behavior. It's a Christian homophobic association pledging to cure the disease of homosexuality. That's ignorance and political influences in science at its finest and it gives all researchers a bad name.

In fact, there are multiple studies that suggest sexual orientation is largely determined by genotype.
http://www.gghjournal.com/pdf/volume_10/10-2/ab2.pdf
http://www.nel.edu/22_6/NEL220601R02_Dorner_.pdf
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1778227&dopt=Books
http://jom-emit.cfpm.org/2001/vol4/gatherer_d.html

In each of these studies, the statistics clearly show a strong relationship between genetics and sexual orientation. You have to think about that twin study you have reported. Almost all behaviors differ with identical twins to a point that makes it impossible to determine any that are purely genetic. To state that twin studies demonstrated a 38% concurrence based solely on genetics says a lot. That finding has been SIGNIFICANTLY distorted in the article you have quoted. 38% is an especially high concurrence in ANY behavioral twin study.

If these "researchers" had any ethical responsibilities at all, they would have reported the p values with that finding. The p value, as it's called in statistics, predicts how likely a given result is due to chance and how likely it is due to the variable being observed. The lower the p value, the less likely the findings are due to chance. I have found several studies refuting evidence that sexuality is genetic, but after reviewing them (and I have reviewed over a dozen) I found multiple holes in the research, mostly relating either to shoddy study designs or inaccurrate reporting of the statistics involved.

Scientists have a fundamental responsibility to make factual observations by accurrately reporting all findings and the what can really be determined by them. These researchers disgrace the scientific community by presenting a religious and political bias aimed at intentionally corrupting the information we have available. It's sickening and I'm personally offended that anyone with such atrocious research ethics can call himself a researcher.

 

[ski2bfree]

Based on the evidence I've seen, theory #3 matches observations far better than #1 or #2.

I agree with your assessment, except that genes are mostly expressed through hormones. A person's genes contribute to the physiology of the hypothalamus and pituitary gland, which control the hormonal cycle in the body by signalling endocrine glands throughout the body to produce or cease production of hormones. In addition, the structure of the proteins that recognize hormones is influenced by genes.

 

[Guest]

If I were you, I'd be a little skeptical about anything that NARTH has to say about homosexual behavior. It's a Christian homophobic association pledging to cure the disease of homosexuality. That's ignorance and political influences in science at its finest and it gives all researchers a bad name.

In fact, there are multiple studies that suggest sexual orientation is largely determined by genotype.
http://www.gghjournal.com/pdf/volume_10/10-2/ab2.pdf
http://www.nel.edu/22_6/NEL220601R02_Dorner_.pdf
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1778227&dopt=Books
http://jom-emit.cfpm.org/2001/vol4/gatherer_d.html

In each of these studies, the statistics clearly show a strong relationship between genetics and sexual orientation. You have to think about that twin study you have reported. Almost all behaviors differ with identical twins to a point that makes it impossible to determine any that are purely genetic. To state that twin studies demonstrated a 38% concurrence based solely on genetics says a lot. That finding has been SIGNIFICANTLY distorted in the article you have quoted. 38% is an especially high concurrence in ANY behavioral twin study.

If these "researchers" had any ethical responsibilities at all, they would have reported the p values with that finding. The p value, as it's called in statistics, predicts how likely a given result is due to chance and how likely it is due to the variable being observed. The lower the p value, the less likely the findings are due to chance. I have found several studies refuting evidence that sexuality is genetic, but after reviewing them (and I have reviewed over a dozen) I found multiple holes in the research, mostly relating either to shoddy study designs or inaccurrate reporting of the statistics involved.

Scientists have a fundamental responsibility to make factual observations by accurrately reporting all findings and the what can really be determined by them. These researchers disgrace the scientific community by presenting a religious and political bias aimed at intentionally corrupting the information we have available. It's sickening and I'm personally offended that anyone with such atrocious research ethics can call himself a researcher.

Son, you would make a Father proud!:applaus:

As a matter of fact it was so well researched that I left your entire quote as I felt it was worthy of a second read for those who merely glanced at it the first time.

I would have added positive to your reputation , however it seems I have to spread more reps around before adding to yours again! Bravo on your work! A+++ :thumbsup: :eusa_clap

 

[smo1704]

I agree with your assessment, except that genes are mostly expressed through hormones. A person's genes contribute to the physiology of the hypothalamus and pituitary gland, which control the hormonal cycle in the body by signalling endocrine glands throughout the body to produce or cease production of hormones. In addition, the structure of the proteins that recognize hormones is influenced by genes.

The primary problem with the genetic theory is that it does not explain the prevalence of homosexuality. If we look at homosexuality in animals (in which case we can ignore the complexity of human behavior) it is simply too common to be hereditary considering that the gene would prevent those that express it from reproducing. Similar genetic traits that prevent an individual from reproducing such as those that leave an individual sterile or cause them to die young (or even traits that make survival improbable, such as albinism) only occur in small fractions of a population, far less than even 1%. Yet homosexuality has been observed in as much as 10% of the duck population. There's simply no way that's genetic. A homosexuality gene should be self-extinguishing, yet homosexuality seems to maintain the same level of prevalence in a given species.

 

[Guest]

I tend to disagree about the point that homosexuals do not reproduce.Gay men and women do produce children. Not all **** are parents but a great number of them do have offspring.

The number of "married" homosexuals with children would be staggering if those still in the closet were to be counted. The offices of psychiatrists world wide have married "gay" men in the waiting room struggling to come to grips with their "secret" lives.

 

[smo1704]

I tend to disagree about the point that homosexuals do not reproduce.Gay men and women do produce children. Not all **** are parents but a great number of them do have offspring.

The number of "married" homosexuals with children would be staggering if those still in the closet were to be counted. The offices of psychiatrists world wide have married "gay" men in the waiting room struggling to come to grips with their "secret" lives.

That is exactly why I used homosexuality in animals. Human behaviors are much more difficult to model, as there are countless outside factors that are difficult to measure and account for empirically. In animals there are outside factors associated with behavior, but for the large part, behavior is based on instinct

Note to PETA: This is a big reason for animal testing. Humans make lousy, overly complicated, test subjects.