Question about homosexuality and genetics?

Question

Has the gene been found that causes homosexuality? If it has, I'm wondering how it is passed on (even if it is recessive), given that the vast majority of homosexuals do not procreate? I don't know much about genetics, but it seems like a strange problem. If you have any insight, I'd appreciate it. Thanks!

Answer 1

You have gotten pretty good answers. Just remember that after the human genome project we know pretty much know what the genes do, and there isn't one for homosexuality. Some studies suggest that certain parts of the brains of homosexual males are similar to those of females. However, they also found alot of straight guys with the same brain function. It is likely a combination of different non genetic influences like the others suggested.

Answer 2

It's pure speculation that there *is* a gene that "causes" homosexuality. Like any other human behavior, this behavior most likely comes from a combination of heredity, upbringing, culture, and lots of other influences. That doesn't mean it's a "choice" (although for some indviduals it is), or that it's not normal, it just means that it's complex. What causes some men to be attracted to large breasted-women, and some to small-breasted women? What causes any of anybody's sexual preferences? It's nearly imnpossible to point to any particular "cause" in all of these, and it's almost certainly not *just* genetics.
Studies have shown that there are some brain structures that are similar in *many* (not all) homosexuals, and research is still continuing, but you're probably going to just have to accept that it's not as simple as you wish it was.

Answer 3

One of the Dateline or 20/20 shows had a segment on about this about 2 months ago. I dont recall it being genetic, but the brains of the people who were gay seemed to be wired different right from birth. (they went back looking at family videos of kids when they were infants and toddlers) It was really interesting because some were obviously different right from the get go. There was a pair of male twins about 8 years old, one played with trucks, the other dolls. They shared the same DNA so it is wild how they ended up that way.

Answer 4

No, exact gene has been isolated. There are stronger theories regarding difference in embrological and childhood development (biological) resulting in homosexuality.

"We favor the hypothesis that differences or variations in genetic patterning of the immature nervous system (probably of the hypothalamus) set the sexual predilection during early life. Several morphologic studies of the hypothalamus are significant in this regard. Swaab and Hofman have reported that the preoptic zone is three times larger in heterosexual males than it is in females, but it is about the same size in homosexual males as it is in females. As mentioned in Chap. 27, LeVay found that an aggregate of neurons in the suprachiasmatic nucleus of the hypothalamus is two to three times larger in heterosexual men than it is in women, and also two and three times larger in heterosexual than in homosexual men. If confirmed, these findings, which have been disputed by Byne, would support the view that homosexuality has a biologic basis. Genetic studies point in the same direction. Pooled data from five studies in men have shown that about 57 percent of identical twins (and 13 percent of brothers) of homosexual men are also homosexual. The figures for lesbians are much the same. The inheritance pattern of male homosexuality comes from the maternal side, implicating a gene on the X chromosome (LeVay and Hamer).

Answer 5

Well, some do have biological children (obviously not with their "partner"). No homosexuality is obviously not hereditary or linked to any one gene. Scientists have done studies than link differences in brain chemistry, and even finger length corresponding to sexuality. Another recent study has shown that the more older brothers a man has, the greater the likelihood that he is homosexual (although they would have to have about 50 older brothers to even reach more than a 15% chance.) Sexuality isn't a physical characteristic, like hair color, height. It's not a medical condition that can be passed on, like depression or breast cancer.
And many diseases that are linked to genetics also depend on the interplay of more than one gene. Sometimes, there is no one gene that you could cut out to prevent a disease, it's complicated. Serious disorders such as Tay-Sach's, Huntington's, have been studied and linked to genetic factors, but more common diseases are harder to pinpoint

Answer 6

There is evidence that homosexuality is genetic. The "Gay Uncle" study is rather famous.

Parents can pass on genes that are not expressed in themselves.

As of now, no "gay gene" has been identified. No "straight gene" has been identified either. I don't know why some idiots think the latter lacks significance.

Answer 7

Sexually speaking, all human fetuses are females until about the 8th or 9th week of gestation. Scientific studies have shown that the level of testosterone a fetus receives at about 9 weeks gestation is key in determining sex and sexual orientation. Higher levels usually mean that the baby will have more of a masculinized brain (showing traits such as greater spatial skills) and those who receive a very low level of testosterone will have more feminized brains (higher speech and communications/relationship skills). This does not guarantee a certain sexual orientation, but makes it more likely.

Answer 8

Yes the gene is called the Matt Martin Gay Gene find out more by mailing or calling

Matt Martin
3704 mount olney lane
Olney, MD 20832

301 814 0280

Answer 9

read this.

http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=306995

this site was written by the NATIONAL INSTUTITES OF HEALTH.

the short version? There are many different types of homosexuality caused by different things.

Answer 10

You answered your own question it is impossible and would need to explain how two identical twins could have differnet sexual orientations.