Thursday, July 23, 2009

Why is it so hard to prove that sexual orientation is genetic?

Scientists today can examine a piece of DNA and say pretty much anything from hair color to shoe size. Thanks for answering my question.



Why is it so hard to prove that sexual orientation is genetic?

because they havent been able to isolate the gene..yet ;)



Why is it so hard to prove that sexual orientation is genetic?

Because Gay people can't produce babies.



Their genetic information isn't passed on.



Why is it so hard to prove that sexual orientation is genetic?

ummmmmmmmmmm wat if its not??????? im the only bi in my family................and besides, isnt it the way of thinking of the person, thier opinion not a physical set of data???



Why is it so hard to prove that sexual orientation is genetic?

Orientation resides in the brain. The brain is the most incredibly intricate structure we have ever attempted to understand.



It is influenced by environment (yes, I do acknowledge that). It is also influenced by genetics, pre-natal influences (the wash of hormones in the womb), and probably more.



That we haven't identified the exact mechanism shouldn't be surprising given its enormous complexity. But we know more each year, and everything I've read in the last 25 years indicates to me a genetic or pre-natal link, and that is also the opinion of scholars.



And btw, we may know the genome, but we can't look at a piece of DNA and say anything about shoe size, or most expressed traits except that the particular piece of DNA is responsible in some way for that particular trait.



Why is it so hard to prove that sexual orientation is genetic?

It's already been proven



Why is it so hard to prove that sexual orientation is genetic?

The Human Genome Project and all these new twin studies have pretty well diminished the role of heredity to insignificant.



the latest twin study (finland) has it that is if one identical twin SSA, the chances are only about 10 percent that the co-twin is gay. Santtila, P., Sandnabba, (2008).



So, 90-70% of gay happens after the womb, the influences are not genetic or hormonal. What could they be? r we going to have an x file here? or could we acknowledge the overwhelmingly obvious?



---family dynamics



Why is it so hard to prove that sexual orientation is genetic?

Because we can't actually look at a gene and determine complex phenotypic results. Most human characteristics are not a single gene, or even a single group of genes. DNA has introns and exons (bits that are added or removed during translation/transcription), some of it is methylated (extra CH3 groups added) and some is not, etc. It's really hard to determine anything from it. The single-gene diseases and characteristics we can predict now are the exception, not the rule.



Why is it so hard to prove that sexual orientation is genetic?

The HGP and several studies lately, including twin studies, are largely inconclusive because no one wants to jump the gun on this one.



The HGP has isolated several genotypes that seem to indicate a genetic predisposition to homosexuality...are these officially the "gay genes" not yet. They need more time to study and research.



Also the Kleinfelter studies seem to indicate the presence of a genetic difference is homosexuals that is not present in heterosexuals. There is also increasing evidence in several recent studies that seem to indicate that the more sons a mother has the higher the likelihood they will be homosexual.



Genetics, as a science, is still in it's infancy and so much more research and study is needed before they can make conclusive determinations.



Why is it so hard to prove that sexual orientation is genetic?

It has nothing to do with genetics, it is a choice that people make its that simple!



Why is it so hard to prove that sexual orientation is genetic?

I think it's because the entire human genome isn't mapped...not yet.



AND...those like our friend, Gary, like to make up numbers to support his opinion.



Explain this one, Gary. I grew up in a family with a mother and father. We lived in the country. Very poor. Never had cable until I was a teen. Never knew what gay was until I was in my teens. Never any association with a known gay person. Never molested. Then.....how am I gay? I knew from as early on as 5 yrs old!!! What made ME gay, if I wasn't genetically predisposed to it?!?!? Please, oh please tell me (since you think you have all of the answers).



Why is it so hard to prove that sexual orientation is genetic?

Traits such as pigmentation and size of feet are straightforward to measure and quantify objectively; in the field we would say that the phenotype is concrete and well-defined. However, many phenotypes involving organismal behavior have a more arbitrary definition, so it's fundamentally more difficult to classify whether a given individual expresses a certain trait or not. This difficulty plagues many studies of human mental and behavioral traits and disorders, schizophrenia and OCD among many many others. At what point could you say that a certain person has OCD? One psychiatrist could say that he is, while another could say he isn't. How do you classify that a person is gay, just because he likes guys in a sexual way? In all circumstances, or at least in certain ones? He must not like women sexually ever (or otherwise be classified as bi)? Or if he has a dream of having sex with a man/woman once per day/week/month, what does it mean about his sexuality? It's not so easy to classify, and there has to be an objective way of measuring it for the science to remain solid. Simply asking the person what his sexuality is is not good enough.



On top of that, people learn coping mechanisms to try to hide behavioral traits deemed (by whatever source) bad, and this adjustment can sometimes make determination of the trait difficult if not impossible. That being said, coping mechanisms are never perfect -- hence our ability to "sense" that somebody may be in the closet, etc.!



In addition to the uncertainty of the trait, most human geneticists would argue that behavioral traits are multifactorial, dependent on multiple genes and on external environment. The technology to determine that a specific gene causes a specific condition was discovered only within the last 30-some odd years; it's considerably more difficult if 5 or 6 genes, working in concert with a specific environmental stimulus, are the causative factors instead.



For ethical reasons, we are limited in the genetic studies of humans scientists are allowed to carry out. We probably know more about mating behavior in the fruit fly than we do about that of humans!



I'm willing to bet that once the genetics of human sexual orientation is sorted out, it'll be revolutionary... that it's determined in a way that very few people would expect.

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