You see problems in the ancient Egyptian kingly lines as well, where brother-sister marriages were expected of the Pharaoh, like Marfan’s Syndrome.
Oh, data4, I never did fully address your statement that homosexuality is a ‘lifestyle choice’ rather than a genetic trait, let me remedy that.
“Either way, the timing suggests that anyone who argues that sexual orientation is a ‘choice’ is clueless.” Blum, D. (1997)
Here is some of the evidence that points ‘towards a genetic, or biological, basis for sexual orientation’ (from Pierce J Howard, Ph.D., The owners manual for the brain: Everyday Applications from Mind-Brain Research Rev III): ’
- Homosexuality runs in families.
- Homosexuality appears randomly in birth order.
- Homosexuals exhibit early childhood gender nonconformity.
- The third interstitial nucleus of the anterior hypothalamus (INAH-3) is of equal size in women and homosexual men but is twice as large in heterosexual men. Homosexual men have fewer neurons in the INAH-3 than heterosexual men, yet more than women.
- Monozygotic (identical) twins have the highest concordance rate; if one is homosexual, there is a 50 percent probability that the other will be too. Michael Bailey reports in March 1993 Archives of General Psychiatry on a study of 71 sets of identical female twins, 37 sets of fraternal twins, and 35 sets of adoptive sisters, each set including at least one lesbian. For identical twins, 48 percent of those identifying themselves as lesbian or bisexual also had a sister who was lesbian. For fraternal twins, this was only true of only 16 percent; for adoptive sisters, only 6 percent.
- Doreen Kimura reports in the December 1994 issue of Behavioral Neuroscience that in a study of the fingerprint patterns of 182 heterosexual men and 66 homosexual men, twice as many homosexual men (30 percent) as heterosexual men (16 percent) showed more ridges on the left hand than on the right (most men show more ridges on the right hand). These print patterns are completely formed within four months of conceptions. Women and gay men have a higher incidence of higher left-hand ridge counts.
- Kimura and Carson (1995) report that both men and women with higher left-hand ridge counts excel at typically feminine tasks such as those involving nurture and verbal skills, and that both men and women with higher right-hand ridge counts excel at typically masculine tasks such as those involving aggression, math, and spatial skills.
- Gays and lesbians have a higher incidence of left-handedness.
- A significant number of gay men hear equally well in both ears (most males hear better through the right ear, most females equally well in both). The latter finding supports earlier findings that homosexual men have larger connections between the two hemispheres.
- Dean Hamer, of the National Cancer Institute, has demonstrated that many gay brothers share a strip of DNA passed down from their mothers. Expanding on this finding, Plomin, DeFries, McClearn, and Rutter (1997) report that such DNA strips-called linkages in reference to the unusually close proximity of the genes-in the q28 region of the X chromosome were shared by 67 percent of homosexual brothers but only 22 percent of heterosexual brothers, a significant difference from the 50 percent standard for independence of association. This research builds on the linkage phenomenon whereby two gene locations are close to each other, which is one way of demonstrating genetic influence of behavior.
- Acoustical researchers Dennis McFadden and Edward G. Pasanen and their team at the University of Texas at Austin placed tiny microphones in each ear canals of 60 homosexual or bisexual women and 57 heterosexual women. The former were shown to emit weaker and less frequent spontaneous otoacoustic emissions that the latter. These imperceptible sounds from the homosexual and bisexual women were more like those of men (April 1999 issue of Journal of the Acoustical Society of America).
- Laura Allen and Roger Gorski of UCLA reported the results of a study they made of the brain tissue of 34 homosexual men, 75 presumed heterosexual men, and 84 presumed heterosexual women (Proceedings of the National Academy of Sciences, August 1992). The anterior commissures (a communication link between the two brain hemispheres) of the homosexual men were 34 percent larger than those of heterosexual men and 8 percent larger than those of the women, whereas the anterior commissures of the women were 13 percent larger than those of heterosexual men. This finding appeared to be confirmed in a later report by Sandra Witelson, Ontario, Canada. Her study was based on a sample of 21 men.
- Four collaborators-laboratories at Standford University, the University of Texas Southwestern Medical Center at Dallas, Brandeis University, and Oregon State University-have reported (in Cell, December 13, 1996) that the male fruit fly (Drosophila) possesses a powerful high-level gene that governs it’s sexual behavior. One mutation of the gene leads to indiscriminate, or bisexual, behavior; another mutation removes the desire to mate; and yet another mutation removes the ability to perform the “courtship buzz.” Fruit flies with all three mutations are perfectly health otherwise. In the first mutation mentioned, indiscriminate males who are confined together without females all engage in the behaviors of courting and being courted by each other.
- Apparently sex hormones are not the sole determining factor. Although there is a small difference in testosterone levels between heterosexual and homosexual groups, a greater difference exists within groups. In one comparative study, the highest testosterone belonged to a homosexual male subject.
- Male homosexuals perform more like females on spatial tasks (i.e., lower than male heterosexuals); lesbians do not show the same pattern (i.e., perform as their own sex).
- Researchers (Nature, March 30, 2000) at the University of California at Berkeley found that men’s ring fingers tend to be longer than their index fingers, whereas in women these same two fingers tend to be about the same length. Among a sample of 720 adults in San Francisco, lesbians tend to show the typical male proportions, with longer ring finger. Interestingly, male homosexuals showed a more “masculine” proportion than male heterosexuals, with the homosexuals’ index finger even shorter than those of heterosexuals. Scientists believe that androgen levels account for the difference, with higher levels during early development of both male and female heterosexuals.
- Among mammals, homosexuality is not an aberration of humans. In a major advance in research, Bruce Bagemihl (1999) has scientifically documented same-sex courting and copulating in more than 450 species of animals. One of his intriguing, but not universally accepted, interpretations is that of “biological exuberance,” or the notion that the world is filled with examples of "excess’ resources, such as the sun, that pour out so much of their essence that multiple uses emerge. Thus, the excessive sexual urge of mammals finds expression in behavior oriented in more ways than reproduction. Blum (1997 p. 130) found that homosexual behavior of some sort has been noted in more that 60 species. ’
So, really, it can still be argued that homosexuality is environmental, but the data does suggest a biological influence. It is not conclusive, however.
And, data4, you said homosexuality is a choice, but that wouldn’t that mean that everyone, gay or straight, would have to consciously decide if they are to be attracted to someone, whether that be a man or women? Or wouldn’t everybody have an attraction to both men and women and choose whether to accept\allow the feelings\attraction to come through, on a conscious level?
Dominick
If the genetic predisposition of this follows the rest of the animal kingdom (and I believe it does) the entire population is expected to have a 2% genetically-determined homosexual component. Since the US population statistic show gays at around 10%, the additional 8% would be lifestyle choice, or other factors influencing sexual preference.
Diane
Actually the statement IS true. I did hear that (or maybe read it). What I heard may not be true, so thank you for clearing things up. Maybe it was propaganda from some incest rights group and I didn’t properly filter it.
I always find difficulty accepting statements as fact when they start, “I heard that…” Facts aren’t about hearsay.
Diane
Gee and I thought people were Homosexual because they had just given up on trying to get laid by the opposite sex…
Oh, and Gay does show up in other species-
Homosexuality does for UK blue duck population ? The Register
I remember reading that in rodent populations the tendency to eat their young and homosexual tendency goes up with the size of the population, so it is nature’s way of controlling the population levels.
Well, the data, at the moment, suggests both a biological and environmental factors, yes, but my question still stands, and Diane I’d like your take on this as well, how can homosexuality be a lifestyle choice? “Wouldn’t that mean that everyone, gay or straight, would have to consciously decide if they are to be attracted to someone, whether that be a man or women? Or wouldn’t everybody have an attraction to both men and women and choose whether to accept\allow the feelings\attraction to come through, on a conscious level”?
Oh, and just a little update on the animal kingdom, 1,500 animal species practice homosexuality.
Actually, all kinds of aberrant behavior crops up when population goes up and resources remain stable. Besides increased homosexuality, you also get early hording by non-breeding, non-homosexual males, and obesity in those members, as well as cannibalism and highly increased incidence of violence and anti-social behavior. These are not really control mechanisms, but indicators of too much stress hormone in in the individuals.
Those things don’t really apply to the US, since other than inner city, our populations are pretty small and stable and resources are high.
I think the rise in homosexuality has more to do with the fact that it is popular right now more than anything, especially in progressive areas where the atmosphere is more liberal.
Diane
I don’t quite get your reasoning.
The research shows that most children, boys and girls begin experimenting sexually with the same sex. This doesn’t imply homosexuality as much as it does curiosity and opportunity. Normally as children mature, boys gravitate towards desire of girls exclusively and girls of boys. This is very much biologically driven.
As puberty approaches boys and girls begin being strongly attracted sexually to the opposite sex, except for those rare cases of homosexuality. In those cases, as the research shows, their brains react very much as though they were actually the opposite sex, including responding strongly to male pheromones (males) or female pheromones (females).
However, about the social issue, I’ll give you a personal example, since I got a really good snapshot of this as it was happening. A few years ago (actually, about 16 years ago) my niece was living with me. She was 18, but had a lot of younger friends who hung out with her, 14-18 year olds, mostly. I became sort of their psuedo-mom, and they all from time to time would sit and chat with me. So, I got a good feel for their social situation and all that jazz.
The younger girls and boys had some very interesting conversations with me about dating and about sexuality (they were taking their first high school sex ed classes). What I found striking was the almost glazed and enamored look in their eyes when talking about homosexuality. At that time exploring homosexuality was the in thing to do, slightly rebellious, slightly defiant, slightly shocking, and a way to make themselves really different from their parents. So, at least for these young men and women it was more of a social statement as a lifestyle choice than an actual biological urge.
I kept a really non-judgmental air during these conversations, mainly because I wanted them to be open and honest. So, I feel that I got maybe a little more information than I would have under other circumstances. And I was very curious about these kids’ attitudes and viewpoints on the world. BTW, these were all really good kids, none that you would expect would ever get into trouble or end up on the streets.
Now all this took place in Seattle, which is a very progressive city. But I can imagine that this same kind of sweeping wave was taking the teens socially in a lot of areas in the country, because of the political and social movements of the gays at that time, and because of the increase in information available through the schools for this heretofore taboo subject.
Anyway, it is food for thought.
Diane
Yes. I should have put more caveats in my post to lessen its weight for other less discerning people 
.
I suspect this is the article I read. I never realized it was from the NY Times. Oops.
Few Risks Seen To the Children Of 1st Cousins - The New York Times
The biologically homosexual men and women… yes.
Ahh, now I see what assumption you are operating upon! You didn’t understand my reasoning, because you believe that the majority of a homosexual population is simply experimenting, making a social statement, as you say.
Now, there is two definitions of homosexuality,
- Sexual orientation to persons of the same sex.
- Sexual activity with another of the same sex.
The GLBT movement is trying to gain rights for the former, while the latter, in reality, is not necessarily a biologically driven act, as you pointed out, so they would not be entitled to such a right. But, I do understand that the ‘8’ percent, you rationally theorized, could take advantage of that right as well; however, that is no reason to deny the right, to biologically homosexuals, to marry. If it is biological, it’s not a lifestyle choice… so how could you deny them any right’s a biologically straight person would have? I believe we need to support those who are not just trying to make a social statement, honestly, I think that is quite disturbing that societal norms, have come to such a point.
You were talking about acts, myself, purely orientation. Of course we couldn’t understand each others reasoning!
Dominick
Okay for clarity, I do not believe the majority of practicing homosexuals are simply experimenting.
What I said was a lot of kids I came across in the very early nineties were experimenting with homosexuality, and that the social changes taking place at that time allowed it and encouraged it, and made it appealing to that group.
I believe that the majority of practicing homosexuals have make a lifelong commitment to their lifestyles. And that is not experimentation.
I’m not here to judge the reasons for that or to judge that lifestyle. But I do believe that if every practicing homosexual were tested with PET scan type tests, only 20% of them would show a biological basis for their homosexuality, and the other 80% would not.
As to your questions… I support equal rights for (same and opposite sex) couples, whether those couples are united in marriage, civil ceremony, religious rite, or whatever under the law. I also believe they should all face the same kind of legal morass when dissolving those unions… heh.
I do not support a small minority forcing changes that will effect the lives of the majority of people. And specifically I do not support changing the legal definition of marriage.
Diane
While I don’t necessarily agree with your agree with your views on the subject, I am glad you joined in on this discussion
I respect your right to have those opinions and will leave it at that, I don’t wish to challenge your beliefs, that would be pointless.
Thank you for helping make this discussion more interesting, Diane! 
Dominick
Ok, ever since this thread discussion, I have not, for the life of me, been able to understand what either of you meant by homosexuality being a ‘lifestyle choice’. If it’s a matter of attraction to the opposite sex… how is that suppose to work? And, if it’s not a matter of attraction, what are you refering too?
I tried to ask this question a few times, earlier in the thread, but it seems I wasn’t stating the question adequetly, because you both said you have no idea what I was try to say 
, my bad. Input on this would be wonderful 
Dominick
Okay, I’ll try to address this to the best of my ability and my understanding.
First the attraction factor: Human beings are different from all other animals in that we are creatures of the mind. And we have the ability to sexualize and become attracted to nearly anything.
About Lifestyle choice: Like any alternate lifestyle choice, that lifestyle choice fulfills complex needs. There are tons of theories why someone would choose homosexuality over heterosexuality beyond the experimentation stage, but I’m not going to go there in detail. I think that it is a personal choice and shouldn’t be generalized and dissected by someone who isn’t that person.
But I do know that every one of my gay friends, acquaintances, and relatives are very complex people with complex ways of perceiving the world and with complex coping strategies. This is very unlike most of my straight friends, acquaintances and relatives who are pretty straight forward (no pun intended) and pretty dull in comparison.
As a whole, though, other than one uncle-in-law, who is an uncomplicated gay man (a rarity), most of the straight people in my life are happier and more contented by far than the gay people in my family and in my life. I don’t know why that is other than the gay people in my family and life are pretty high strung as a whole.
I don’t know if that answered anything for you Dominick, but that is just how it makes sense to me.
Diane
Try checking out some of the fetishes some people have. Do you think beastiality is genetic? I’m not “comparing” it to homosexuality, but you can see how the mind might create attractions. It might not even be a “choice” in the sense that the person decided to do it, but some combination of experiences could have unintentionally anchored a pleasurable sexual response.
I find it hard to see homosexuality as some sort of pseudo-fetish. It’s an attraction to someone… but that just me, we’re all biased in some way.
Then, in that case, if homosexuality were to be classified as a 'lifestyle choice", wouldn’t that imply it is merely a psychological, sexual disorder, and should be classified as a paraphilias?
I don’t like the notion that homosexuality is something to be cured…
Correct me if I’m wrong here…
Dominick
I don’t think fetishes or lifestyle choices are considered anything to be “cured” any more.
Diane