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Homosexuality is not a genetic issue

  1. Jul 3, 2008 #1
    homosexuality is not a "genetic" issue

    Is it safe to say that homosexuality is NOT a "genetic" issue, given the fact that such a gene would never be "passed on", and hence would not survive natural selection?
     
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  3. Jul 3, 2008 #2

    mgb_phys

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    Re: Homosexuality

    Not necessarily.
    In many species only one dominant male gets to mate and pass on their genes, it doesn't mean that this behaviour isn't genetically determined.
    In the same way people living longer than reproductive age isn't directly passed on to their offspring but might have benefits for the gene pool at large.
    Genes are cunning little devils - they always have an angle somewhere!
     
  4. Jul 3, 2008 #3

    Pythagorean

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    Re: Homosexuality

    Also, genes can be passed on but not expressed. I believe most (if not all) of us have genes that might never be expressed before we die, but we will pass them on and perhaps under the right stressful conditions our offspring will express those genes.
     
  5. Jul 3, 2008 #4

    Moonbear

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    Re: Homosexuality

    The only way a gene is prevented from being passed on is if it's lethal prior to reproductive maturity even in an individual heterozygous for that allele. So, no, that's not a safe assumption.
     
  6. Jul 3, 2008 #5
    Re: Homosexuality

    If you start with a healthy group of people with "good genes," and let them reproduce, then generations down the line random mutations should occur producing people with all sorts of traits different than those of the initial group.
     
  7. Jul 16, 2008 #6
    Re: Homosexuality

    Besides what's already been said, there are 2 more reasons why homosexuality could be attributed to genes.

    1. Homosexuals, due to social pressure, often do engage in heterosexual relationships.

    2. Homosexuality, if genetic, is likely not just the result of 1 particular gene that you either have or don't have. It's more likely that it's a combination of many genes together, genes which on their own may only vaguely influence the functions of 1 part of your body.
     
  8. Jul 17, 2008 #7

    Andy Resnick

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    Re: Homosexuality

    I don't think any sort of behavior- use of tools, affinity to form social groups, migration, eating candy corn color-by-color, etc. has been shown to have a genetic origin in higher mammals. At best, some behavior has been linked to specific regions in the brain.

    I had similar (and too short) conversation with a colleague regarding wild vs. domesticated dogs. She discussed "acquired traits" that don't nessessarily have a purely genetic origin.
     
  9. Jul 17, 2008 #8

    Monique

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    Re: Homosexuality

    I've spoken to a director of a neuroscience institute, it is thought among some researchers that homosexuality might be associated with increased fertility, ensuring survival of the trait in a population. I think it will be hard to prove for such complex traits.


    Andy, you don't think that any kind of behavior has been shown to have a genetic origin, that doesn't mean it is not genetic. Currently we do not have adequate tools to find those genes, it is just too complex.

    There are strong indications that behavior is inherited, genetically and epigenetically.
     
  10. Jul 17, 2008 #9
    Re: Homosexuality

    Don't forget about kin selection.

    *EDIT* that was vague, let me clarify -

    my reasoning is that since siblings share genes, a homosexual, non-reproductive sibling might contribute to the spread of shared genes by kin-selection - that is, by focusing more energy on the survival of his/her relatives than if the individual were to be focusing on the survival of said individual's own children.
     
    Last edited: Jul 17, 2008
  11. Jul 17, 2008 #10

    Borek

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    Re: Homosexuality

    That was researched based on Swedish (?) records from 19th century. In families where not only mother, but also grandmother were present at home, number of kids reaching maturity was higher. So long living grandma had higher chances of passing her genes to the next generations.
     
    Last edited: Jul 17, 2008
  12. Jul 17, 2008 #11
    Re: Homosexuality

    So then heterosexuality would not be genetic either?
     
  13. Jul 17, 2008 #12
    Re: Homosexuality

    Sickle Cell anemia and plenty of other genetic diseases still exist despite natural selection.

    Most of the research into homosexuality that I have read about lately points to it as most likely due to natal conditions, not genes of the homosexuality. Hormones help key the development of features specific to males and it seems that if too much estrogen is present at the wrong time or there is some other hormone problem, the child may fully develop male sexual features, but the brain may be altered in such a way that the child is more likely to be a homosexual.
     
  14. Jul 17, 2008 #13

    DaveC426913

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    Re: Homosexuality

    Let's not forget though that homosexuality occurs in nature too.
     
  15. Jul 17, 2008 #14
    Re: Homosexuality

    I think that this has been well-documented. It is pretty absurd, in my opinion, for people to argue that homosexuals do not posses the same kind of innate lusts as heterosexuals. Yet there are plenty of people trying to "cure" them. If there is a "cure" for homosexuality, I can guarantee that it will be fabricated in a laboratory, not a church.
     
  16. Jul 17, 2008 #15

    NoTime

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    Re: Homosexuality

    IIRC the Sickle Cell trait has a positive survival benefit in areas with Malaria present.
     
  17. Jul 17, 2008 #16

    Monique

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    Re: Homosexuality

    There are also cases known where cross-species mating (which results in reduced offspring) actually results in better survival: link.

    Nature sometimes follows counter-intuitive logic.
     
  18. Jul 17, 2008 #17
    Re: Homosexuality

    i think it would be very hard to prove homosexuality is genitic or not because the obvious way to research it is to tell whether homosexuality could be passed down through reproduction... but if the parents are homosexuals and have a child artificially and raise the child... i would think the child would have higher chances of being a homosexual themselves.

    my arguement is that homosexual is not genetic because it wouldnt be passed down... where would it originate? but like was said before... it could be a mutation of other genes...

    I believe like freud said that alot of our personality traits and behavior as an adult is based on events that occur to us as a child... an excellent example is in the movie "as good as it gets" where jack nicholsons neighbor saw his mom naked alot as a child and was around her alot and he became a homosexual... seems pretty logical to me
     
  19. Jul 17, 2008 #18

    Monique

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    Re: Homosexuality

    You are assuming that the genetic trait would be dominant, which it clearly is not.

    Where do you think your gender-preference comes from? Why do most people/animals choose the opposite sex as their mate? You think it is entirely formed by the environment? I don't think so.
     
  20. Jul 17, 2008 #19
    Re: Homosexuality

    I think it is very important to consider that the genome can be though of as a recipe, rather than a blueprint. Buildings are built using a blueprint, which means that we can look at the blueprint for a specific section, and then look at the building to see the specific place. When it comes to the genome, it is different. There is no one-gene-one-trait relationship, but it is often the case that one gene influences several traits or that one trait is influences by several genes, or both. A recipe for chocolate cake can say that you need 1 melted chocolate bar, but in the cake, you cannot point to the chocolate bar in the same way you can point to something on a blueprint.
     
  21. Jul 17, 2008 #20

    Andy Resnick

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    Re: Homosexuality

    A legitimate question. *Reproduction* is clearly the goal of every living thing. Methods of reproduction clearly evolved, but I would not claim there is a gene that governs reproduction . There are genes that control the cell cycle, tho.
     
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