Study examines brain differences related to sexual orientation
This post summarizes a new study by Ivanka Savic and Per Lindstrom, titled “PET and MRI show differences in cerebral asymmetry and functional connectivity between homo- and heterosexual subjects” and published in the Proceedings of the National Academy of Science. This is being reported widely in the press.
The abstract reads
Cerebral responses to putative pheromones and objects of sexual attraction were recently found to differ between homo- and heterosexual subjects. Although this observation may merely mirror perceptional differences, it raises the intriguing question as to whether certain sexually dimorphic features in the brain may differ between individuals of the same sex but different sexual orientation. We addressed this issue by studying hemispheric asymmetry and functional connectivity, two parameters that in previous publications have shown specific sex differences. Ninety subjects [25 heterosexual men (HeM) and women (HeW), and 20 homosexual men (HoM) and women (HoW)] were investigated with magnetic resonance volumetry of cerebral and cerebellar hemispheres. Fifty of them also participated in PET measurements of cerebral blood flow, used for analyses of functional connections from the right and left amygdalae. HeM and HoW showed a rightward cerebral asymmetry, whereas volumes of the cerebral hemispheres were symmetrical in HoM and HeW. No cerebellar asymmetries were found. Homosexual subjects also showed sex-atypical amygdale connections. In HoM, as in HeW, the connections were more widespread from the left amygdala; in HoW and HeM, on the other hand, from the right amygdala. Furthermore, in HoM and HeW the connections were primarily displayed with the contralateral amygdale and the anterior cingulate, in HeM and HoW with the caudate, putamen, and the prefrontal cortex. The present study shows sex-atypical cerebral asymmetry and functional connections in homosexual subjects. The results cannot be primarily ascribed to learned effects, and they suggest a linkage to neurobiological entities.
Past research has found that male and female brains are different, on average. This research finds that two brain measures differ based on sexual orientation: cerebral symmetry and how the amygdala functions. First, they confirm a previously reported sex differences in cerebral size asymmetry. In straight men, the right hemisphere is greater than the left and in women, they are the same size. Savic and Lindstrom find in contrast that gays are sex-atypical: the hemispheres are the same size in gay men and for lesbians, the right hemisphere is larger than the left. This is not unexpected given the previous differences in verbal skills (favoring gay males over straights) and visuospatial tasks (favoring straight males).
The amygdala is often researched in relation to the role it plays in emotion and anxiety. Recent research indicates that the right amygdala activates in men and the left in women during the processing of emotion. From these locations in the amygdala then connections are made to other regions in brain which again are different in men and women. In women, the connections may be more likely to activate emotion, whereas in men action may be the more likely result. Again, Savic and Lindstrom found sex atypical function for gays and lesbians. Gay men looked like straight women and lesbians looked like straight men, albeit the similarity was less for the lesbians.
What does this mean? The authors are cautious in their discussion and make some points which could support multiple theoretical perspectives. The authors examined aspects of brain functioning not known to be related to sexual behavior or attraction in order to reduce the possibility that sexual experience contributed to the development of the differences. In other words, it is unlikely that being homo or heterosexual caused these differences. The differences likely precede awareness of sexual orientation, according to the authors. I would agree that it seems unlikely that there is anything about sexual fantasy or behavior that could rewire the amygdala or change the size of the right hemisphere.
On the other hand, Savic and Lindstrom are not proposing that these differences cause the sexual orientation differences. Those familiar with Daryl Bem’s exotic becomes erotic theory will see how these brain differences could support his theory. It is plausible that these brain differences are involved in the gender atypical behavior so commonly and strongly associated with the development of adult homosexual orientation. Gender atypical behavior could be an associated feature of a same-sex orientation, a kind of sign of homosexual orientation or in the EBE account, gender atypical behavior and interest could predispose people to sexual regard the same sex as the other sex during pubescence.
Savic and Lindstrom propose three potential mechanisms for these differences. They note:
The mechanisms behind the present observations are unknown. In accordance with discussions about the sexual dimorphism of the brain, three factors have to be taken into account: environmental effects, genetics, and sex hormonal influences.
These are the usual suspects, genes, environment and hormones. Savic and Lindstrom dismiss genetic factors for reasons I cannot quite figure out. They say,
As to the genetic factors, the current view is that they may play a role in male homosexuality, but they seem to be insignificant for female homosexuality. Genetic factors, therefore, appear less probable as the major common denominator for all group differences observed here.
About environment, they observe that sex-based brain differences have been observed at birth and in children. However, cerebral maturation continues through puberty, especially in boys. Thus, social and environmental factors could play a role in how these differences or other differences not assessed here develop in individuals. They are not certain however and note:
However, to attribute such effects to the present results would require a detailed comprehension of how specific environmental factors relate to the four groups investigated, and how they affect various cerebral circuits. In the light of currently available information this can only be speculative.
In other words, we do not know what environmental factors could be influential on brain differentiation for male and female with sex typical and atypical brain structure and function. The authors are either unaware of Bem’s EBE theory or do not see it as relevant to their findings. Clearly, these wanted to rule out the role of sexual behavior and preference as being the driver for the differences between gays and straight that they found in their pheromone studies. Here they believe they have found clear neurological differences which in some manner relate to the differences in sexual preferences.
The authors seem more disposed to hormonal mechanisms. They discuss hormonal factors in animals, but correctly note that the relevance to humans “remains to be clarified.” They conclude:
The present study does not allow narrowing of potential explanations, which are probably multifactorial, including interplay between pre- and postnatal testosterone and estrogen, the androgen and estrogen receptors, and the testosterone-degrading enzyme aromatase. It nevertheless contributes to the ongoing discussion about sexual orientation by showing that homosexual men and women differed from the same-sex controls and showed features of the opposite sex in two mutually independent cerebral variables, which, in contrast to those studied previously, were not related to sexual attraction. The observations cannot be easily attributed to perception or behavior. Whether they may relate to processes laid down during the fetal or postnatal development is an open question.
In a post to come, I want to bring together the Langstrom et al study of Swedish twins and the Savic & Lindstrom study. We have many coming to the conclusion that brain differences confirm innate sexual orientation. However, the study of twins seems to demonstrate a role for a variety of environmental factors which operate differently for different people.
This is so awesome, I don’t even know where to start.
I am open to the fact I could be wrong but I doubt increased femininity in males is a susceptability factor for homosexuality. More feminine brain structures, increased left handedness, finger length differences, etc. etc. are all probably a byproduct of whatever triggers homosexuality.
Also, I’m not leaning towards a prenatal, environmental explanation. If we are talking about environment it almost HAS to be the result of something after a child is born. Identical twins are only about 20% concordent for SSA. The other Swedish study suggests that SSA is about 2/3rds environment. That’s childhood differences, not prenatal differences where nearly everything is the same most of the time.
My observation is that youth tend to live up to (or down to) the expectations of significant persons in their lives. Our culture has drawn the lines between “feminine” and “masculine” characteristics, so certain expectations are imposed on developing youth. The current emphasis on divisions by sexuality (GLBT etc.) has to part of the equation. Surely there are increasing numbers of persons identifying with one of these “orientations” simply because they don’t fit the “masculine” or “feminine” categories closely enough. So if brain structure is more random than fits our definitions of gender, we categorize more “orientations” to include everybody.
However, sexualizing our natural attractions toward others is another development within pop culture. “Best friends” and “buddies” get pushed into “sex partner” relationship expectations.
Is Dave G. gay? I ask because he seems to have little understanding of the actual experience of being gay.
The GLBT designations are not “divisions”, they are descriptions of the direction of our natural attractions and feelings — just as “heterosexual” is a description of what straights naturally feel.. And gay people don’t get “pushed into sex partner relationship expectations”, they volunteer. (1-2-3-4)
Would he say that straights sexualize their natural attractions to each other and that they are pushed into it?
Dave G
In many cultures being gay will get you killed and probably in a very unpleasant way. And yet there are gay people everywhere. Where did gay people come from in 1950 with the nuclear family was intact and John Wayne was the nations role model? EVERYONE is strongly pushed towards heterosexuality from day 1.
Experimentation may be driven by pop culture (see this for instance) but I am skeptical that an enduring orientation could be set by it. Drowssap has a very good point I think.
I’ll be curious to see how Focus on the Family and Exodus deal with this one. Ah, never mind. They’ll just ignore it since it goes against what they think. Truth doesn’t seem to be a consideration for them. After all, FotF has been caught in blatant lies that they have refused to set straight, like when they said anthropologists support traditional marriage. Honesty is the first casualty of war.
Warren
Well, I hope it’s not my last… but it might be so I’ll savor the moment.
BTW I clicked the link… Oh man, I thought that was a joke at first. I guess I’m an exile from pop culture.
Prepubescent children are attracted to one another, but it’s not sexual nor gender-specific. GLBT is a later categorization.
Not all 1950’s families were intact, only there were more so. And there were fewer GLBT’s.
Individuals seeking love and being loved, belonging and sure identity, can gravitate toward any relationships that offer satisfying fulfillment.
Warren,
I beg to differ with you, I think pop culture over the past 10-15 years has had a great deal to do with attraction trends and orientation. There may be a predisposition to sensitivity in some individuals that make them more likely to accept these character traits than others. I also believe that is why there are differing levels of attraction found in different individuals and as I have stated before and as the work of Robert Epstein would support the level of fluidity of ones attraction varies from individual to individual. It is for this reason that I am so much against the stereotyping by some on the left who can’t accept that not everyone who experiences same-sex attraction necessarily wants to accept this to mean they are gay. Of course this is all my own opinion and as I have seen in the past that really does not have much value by some, even though the science would support this.
Dave G.
No doubt that applies to a few people but 2% to 4% of the entire male population? Do gay men strike you as bad looking and unable to meet women? If anything gay men are BETTER looking than straight guys and should have no problem attracting women.
When I was growing up in the 80s the stereotype was that if a guy was too good looking he was probably gay. I believe research has found a kernel of truth in that assumption.
concerned
IMHO pop culture has a greater affect on women’s orientation than men only because it appears women are more fluid.
But it’s been my experience that most guys know exactly what they like at an early age and it changes very little. The attractions I felt as a teenager are the same today, 20+ years later.
Warren,
A bit curious here: what does your experience tell you with those you have counseled? Are you publishing this entry because you do believe that the scientific findings may indeed be accurate — that orientation is innate for a good number of folks — or are you simply more open minded than Dr. Dobson and Focus, unwilling to state that “no one is born gay”?
And if so — could or would you share with us sometime (maybe now
what led you to the conclusions you now have which I feel may very well be very different than when you started.
I don’t peruse blogs as often as many do, so I am a bit perhaps not up to date on where you stand with the biological testings and what that might mean for people of faith.
Thank you!
I maintain that a male who is a Kinsey 0 will not be massively impacted by pop culture’s acceptance of homosexuality. At one time, I thought kids were more influenced in this way but I am not so sure now. I do think kids who are already same-sex attracted can be behaviorally influenced but I am not sure that I think someone without SSA can develop it via a social learning paradigm. Furthermore, even if that was possible, it is hard for me to see how homosexuality looks attractive in the small towns and rural areas where I live. It is very hard to be same-sex attracted in a small town or rural area. None of the families I have worked with in the past several years could support such a view. Now, I do think morality about sexuality can be impacted by urbanicity (Frisch & Hviid’s Danish study comes to mind).
AM - I am not concerned about where the research goes. I have seen the biological research quality improve a great deal in the past 4 years and it does appear that biology has a role. I am not a reparative drive theory supporter and think that different factors (pre- and post-natal) operate differently for different people - I think there many different pathways to our sexual attraction patterns.
OK. I reread the study and I have a few more points to make about the amygdala differences.
In the Safron et al. (2007) study we had an event-related measurement of amygdala activation, so the stimuli played a central part in the experiment, showing a marked difference in the way gay and straight men’s amygdala reacted to sexually preferred, sexually non-preferred and neutral images. Overall, gay men’s amygdala reacted more strongly both to men and to women. In other words, their emotional response to preferred images (men) outshot the emotional response of straight men to preferred images (women), but also gay men had a stronger emotional reaction to non-preferred images (women) than the straight counterparts to men.
Now — in the experiment set up by Savic, we can see measurements of regional cerebral blood flow (rCBF) in the amygdala when the subjects are lying in a resting position and breathing. Without any other stimuli, the amygdalas of homosexual men still show very marked differences in rCBF compared to heterosexual men. I think that settles the question that Safron et al asked whether this region should be studied separately for possible influences on sexual orientation in males. The genetic linkage study should definitely have something related to that, unless it’s caused by hormones or by environmental stress.
#Hypothesis 1 : A few genes involved in mood disorders should be found on the X chromosome; mutations expressed in the amygdala could account for a greater susceptibility of gay males to stress and early childhood apprehension in front of typically more aggressive boys. (You may laugh, but they were already found in the same-sex oriented drunken fruitflies, and their homologues are already linked to panic and mood disorders in men. Maybe it’s a coincidence…)
#Hypothesis 2 : The stronger emotional reaction in the amygdala is caused by a failure of another brain region to filter the stimuli out before they get in that area and cause panic. I’m not a professional, but I know there is a connection between the stress system and the brain areas that sustain aggressive behaviour and assertiveness. So whatever causes less aggressiveness also makes people fall back on the stress system. They can’t ride the stimuli punch, nor hit back, so they take the blow. This must explain why gay brains react like straight female brains: they both have in common less aggressiveness. There is no need for brain feminization to get this effect in males, at least not in that area. Lower aggressiveness makes them process emotional stimuli similarly.
Also: Creative people have low latent inhibition: they have a hard time filtering the stimuli overload, so they deal with it either by organising them in patterns and using them to do creative stuff or by going nuts. The greater number of gay people in the artistic world and in other intellectual areas could point to lower latent inhibition, because of less aggressiveness.
I’ll come back, when I’ll get the time, to think about possible influences of handedness. This is one interesting piece of research — it brings new correlations, it confirms older ones and opens new avenues for research.
Nick R
Maybe this:
John Maynard Keynes
“When the facts change, I change my mind. What do you do, sir?”
Or maybe this:
Winston Churchill
“Man will occasionally stumble over the truth, but most of the time he will pick himself up and continue on.”
Realistically the two Swedish studies didn’t skewer Narth’s beliefs, they skewered EVERYONE’S beliefs. Both studies discounted genetics & socialization as primary factors.
What homosexual women and heterosexual men have in common: less amygdala activation and greater androgen effects on brain organisation. Therefore, similar rCBF patterns in the Amy. Gay men and straight women have in common less androgen effects on brain, so amygdala patterns should look similar because less aggression in the brain must cause similar sensitivity via less capacity to filter out stimuli. Since the proposed X-linked deficient gene expressed in the amygdala to produce greater sensitivity in gay men cannot be extended to straight women to account for the similarity in stimuli response (it would be silenced), and neither can such mechanism be supposed to play a part in the different similarity between straight men and gay women responses, then hypothesis #1 must be scrapped.
Looks like it’s headed towards hormones, or whatever can mess with the system that modulates aggressiveness. Including environment and factors that either make the person catch the windows of opportunity to develop sex-typical aggressiveness or miss it. People could experience that at different ages, with different intensities. The GID kids must be the tip of the iceberg here. Some gay adults may not have been atypical during childhood, but somehow got diminishing returns. We may one day return to that Freudian ‘arrested development’ phrase…
Evan - I was with you until you got to Freud.
I suspect there are other means to influence amygdala development which have little to do with externally obvious sex typical/atypical behavior. Trauma could be one but I suspect there are others which would not be obvious at all. Aggressive gay men may have a different pathway altogether…
Evan
I believe it could be an infant’s hormones or some force that disrupts these hormones, but how could it be prenatal hormone levels?
Identical twins are concordant for SSA just 20% of the time. How could the womb environment be so different most of the time?
I’m not saying it absolutely can’t be prenatal. But if we know that SSA is largely environmental isn’t the safe bet the post-natal environment? That’s where children experience significantly, different variables.
Evan:
Interesting hypotheses.
One correction: homosexual men had less amygdala activation than did heterosexual men for nonpreferred sexual stimuli.
Graph of evoked activity looked something like this…
Homo male-stimuli: iiiiiiiiiiiiii
Homo female-stimuli: iiii
Hetero male-stimuli: iiiiiiiii
Hetero female-stimuli: iiiiiiiiiiiii
Warren,
Well, I mentioned Freud only for the phrase that could be reconsidered in a different light one day, surely not for the parental effects on development or any other theoretical load.
I remember once watching a very interesting debate on temperament development and a lady that was an expert in pediatrics and child psychiatry mentioned a case in which a child’s temperamental development was disrupted just because of one accident: a suspended toy falling on the baby. The link to the debate is here (1h:56min.)
As for aggressive gay men, a possible indirect explanation: there are studies that showed counterintuitively that, on average, imprisoned people are lower on circulating levels of testosterone, so their aggressiveness was due to compensating behaviours. Many instances of aggressiveness are caused by deficits rather than overexpression.
Adam Safron,
Thank you. Great piece of research! Sorry if I misrepresented it.
I think I misremembered the graph for amygdala activation. I checked right now and I think I mistook the page 5, Figure 1 A, Subjective Liking/Disliking graph, with the one from page 9, Figure 3, presenting brain activation on an average basis.
Interestingly enough, the differences in activity between categories are not great in magnitude. Heterosexual males seemed to ‘warm up’ more to stimuli discordant for their sexual orientation than homosexual males did. But then, again, homosexual men reacted stronger to preferred stimuli. Actually both heterosexuals and homosexuals reacted more strongly to male stimuli, LOL!
Drowssap,
I can’t anwer your questions without speculating too much. I recommend you watch the debate on temperament development, moderated by Prof. Donald Pfaff. It touches on many of these questions, and the participating researchers or clinicians address them from many perspectives.
Evan
To be perfectly honest everything I say is pure speculation.
But I try to make it sensible speculation at least.
I’ll watch the Pfaff thing Thursday. I loaded it up from your first link but it was over an hour long and it’s bed time for me. Tomorrow I’m in the field all day working. Uggh! But Thursday I’m on it.
BTW, I look forward to Neil Whitehead’s take on the two new Swedish studies. I think these studies created a seismic shift in the science of SSA.
Evan,
Thank you for the link on temperment. It is long so I have not watched all of it yet. The hormonal influence is extremely interesting and when tied in with the trama in earlier childhood I believe it says a lot about why I do not think we will find answers by continuing to focus on genetics. This is something that has been at the route of my own journey away from acting on my same-sex attraction. So much of what they are saying here makes so much sense and confirms much of what I have discovered for myself and have seen in others who begin to take responsibility for their lives. It is not an easy journey but it has been well worth it. The biggest part for me most of my adult life has been a lack of a sense of belonging. Now that has improved and I am feeling more connected with humans and no longer need my old ways of relating to people. It has been a combination of understanding the true science and returning to my religious routes and understanding how the two are not opposed to each other but simply look at the same questions in differing ways.
Once again thank you.
Concerned,
You’re welcome.
I am of the same opinion as you, that actually science will lead people to a sort of halt, an open window they will finally reach, look through and exclaim: Oh-my-God!
Evan,
Nicely put!
Concerned
Forget about homosexuality. Pretend we are talking about any common, worldwide phenomenon that significantly reduced the chances men would have offspring. It doesn’t matter the reason. Genes are the last place we would expect to find a definitive cause. It’s no surprise to anyone who has read even a paragraph on evolution that genes didn’t pan out as a prime mover.
Concerned
Uh… I just re-read my message and maybe I came across harsh. That was supposed to be read in a light hearted manner. I was agreeing with you.
I wasn’t aware that science became the new god
As someone who actually works in the scientific field (Toxicology), I recognize science for what is it is - another human endeavour that is subject to the same limitations and failings that all human projects are.
Patrick,
It’s a long story. It’s about how people relate to veracity in each epoch. In very simple words, the Ancient Greeks used to relate to things (’ta onta‘) and to becoming (’phusis‘) in many ways, that included gods, myths and mastery of things by ‘art’ or what we call today technics. In our times these things have become split, although they unconsciously relate to the same thing. Former mainstream religious beliefs have survived in institutionalised forms but they sometimes are regarded as conservative because science that was banned from the realms of belief came back with a vengeance, building on facts and experiments (you may compare them with a layman’s circus, because they prove reality in front of anyone, but also with illusionism, because they can craftly use facts to give you an impression of truth). I think science is blindly looking for God, for what it cannot explain, but it’s too early to say.
Now back to the amygdala and brain assymetry stuff.
Drowssap,
No offense taken as I agree and have felt this to be so for some time now. There are more important external factor that must be looked at and have been ignored because of the effort to prove a genetic link. The genetics play a role, but not unlike cancer, the environment is likely what is triggering the ultimate outcome. I suspect that stress and oxytocin, or a lack of it, is a major factor is this triggering.
Here are a few more thoughts on this study:
If you look at the volumetric values for both cerebral hemispheres, you see the pattern of asymmetry is not the same in magnitude for heterosexual men (HeM) and homosexual women (HoW). Also, the standard deviations for homosexual men (HoM) are greater than the standard deviations for HeM. It means the spread was larger for HoM, in fact it was the largest spread. I want to see the degree of overlap between the HoM and HeM groups. The spread for each category could overlap with the spread of volumetric values of other categories of orientation (although each category is positioned extremely on the Kinsey scale!). Some HeMs could overlap with some HoMs which could overlap with some HeWs which could overlap with some HoWs. For the right hemisphere, it should look something like this:
HeM_________
__HoM_______
_____HeW____
________HoW_
I think we can find some significance beyond similarity in asymmetry between HeM and HoW. The absolute values of hemispheric volumes could also be significant. Assume homosexual women have androgenised brains. They also have the smallest mean value of all categories in hemispheric volume. One might have thought they should be closer to homosexual men and above heterosexual women in tendency. But they’re not. Researchers do not explain that, which could confound their findings. Surely, homosexual women’s asymmetry is a lot smaller in magnitude than heterosexual men’s.
Some questions:
Does having greater volume in areas that manage spatial orientation influence how stimuli are filtered before emotions/actions are felt/projected? If it’s true, then greater overall hemispheric size is not as important as relative differences between regional sizes, if that influences stimuli processing or projection of conspecifics in someone’s mind.
This has a potential to match conclusions from LeVay’s 1991 study and the studies that followed. INAH3 dimorphism was found in size differences between presumed homosexual and heterosexual men. Later studies found the difference was not significant in the neural count, but in volume. The neurons were on average more densely packed in the gay INAH3. It could be a similar situation with the underlying regions in the right hemisphere that create asymmetry in heterosexual men and less asymmetry in homosexual men. But the asymmetry magnitude in homosexual women is a lot smaller than for heterosexual men, which should contribute less to the same orientation effect. To conclude — homosexual women do not have «masculine brains» by absolute hemispheric volume, and the asymmetry tendency is smaller compared to heterosexual men’s asymmetry. This either correlates weakly with attractions or homosexual women’s attractions to women are weaker than heterosexual men’s attractions to women.
Another hypothesis:
Relative differences between brain regions produce relative emotional effects by variability in sexual objects. To put it simply, if a heterosexual man sees a bigger attractive man the stimuli are processed differently than if he sees a smaller unattractive woman. If a homosexual man sees a smaller attractive woman or a bigger unattractive man, the effects should be different in gender impression. Or maybe they work in a compound way. Aggressiveness could be an intervening variable that works together with spatial orientation to influence how stimuli are filtered by the emotional brain: impressive but unattractive, attractive but unimpressive, impressive and attractive, and so on. Someone could see an attractive person that might not be impressive enough to spark arousal. Impressionability might depend both on different thresholds set by anatomical and functional relative differences and by variability in the perceived sexual objects.
######
Handedness must also play a very important role in emotional assessment of stimuli. Depending on lateralization of functions in each individual or how they developed separately, emotional response might be different inside each category of orientation. There is a study that shows lateralization can influence emotional assessment of stimuli. Asymmetry in hemispheric volume might have different effects in different sexes, according to handedness. Researchers must put all the facts together in any given individual to predict orientation, because averages might be tricky. If self-reported values for orientation were reflected in brain organisation, then there should be no overlaps between these four categories.
concerned
Bingo! That’s the equation for virtually every common thing.
I personally think the ball is set in motion by something as lame as a common cold or flu virus during pregnancy or in a very, young child. However I would never discount stress. It might directly lead to SSA or just hose our resistance to what does. Stress is like miniature AIDS, it reduces the bodies immune system so that other things can kick our butt.
Side note:
What if 2% to 4% of the male population had no significant interest in any type of sex for their entire lives? Or what if the same percent of men produced sperm that rarely impregnated women? If anybody suggested these traits were spread around the world through genes scientists would laugh at them.
Sure there are probably dozens of susceptability genes but a true “gay gene” is hokum. Studies prove this over and over again.
You don’t think a bug is any more laughable a situation, Drowssap? The bug would have to be present in nearly all countries affecting the each population in about exactly the same way - what are the chances of THAT happening?
How many times do we have to repeat ourselves that no one on here believes in ONE gay gene. No behavior - NONE - is likely to be driven by ONE gene - each behavior is influenced by a group of genes interacting with their environment.
LOL - This study proves, maybe for the first, time, that homosexuality is hardwired in the brain, even before birth.
Concerned and Drowssap -
Not all cancers are driven primarily by the environment - there are small percentages of some cancers that are actually driven by genetics - by this I mean genes play a stronger role it seems than does the environment
jayhuck - the study does not demonstrate homosexuality is hardwired into the brain before birth.
It could be a step toward such a finding but even the authors do not go that far with this work.
Evan,
For someone who claims not to have a good grasp of the English language, you definitely type as if you do.
Someone could see an attractive person that might not be impressive enough to spark arousal. Impressionability might depend both on different thresholds set by anatomical and functional relative differences and by variability in the perceived sexual objects.
Isn’t is possible to recognize something as attractive and impressive without attaching any arousal to it? Women seem to do that all the time. Men don’t do it as much in this country, but can be seen doing it in others.
Drowssap,
Erm, I read in a study that asexuality is around 1% in the population, but it’s probably more, just like many other things that go less reported (I also remember an article about British people being uncommonly more asexual than others). It’s too bad scientists don’t study so much this interesting category. They should study all of them together. They’re probably part of the continuum somehow going from heterosexuality, bisexuality, asexuality, homosexuality to transsexuality.
Genes sure must play some role in predispositions, but my bet is whatever variance in sexuality we find is linked to aggressiveness, because sex-and-aggression is the most widespread cocktail in the animal kingdom. It’s everywhere from lizzards to monkeys. Agressiveness Hormones.
BTW, the guy who argues for the greater female fertility effect, Camperio Ciani, published a new paper on the same topic.
Warren,
This is a quote from the New Scientist:
” The scans reveal that in gay people, key structures of the brain governing emotion, mood, anxiety and aggressiveness resemble those in straight people of the opposite sex.
But until now, the question has remained as to what came first, the orientation or the brain development.
To get round this, Savic and her colleague, Per Lindström, chose to measure brain parameters likely to have been fixed at birth.
“That was the whole point of the study, to show parameters that differ, but which couldn’t be altered by learning or cognitive processes,” says Savic.”
My apologies if I overstated the results, but this quote is still powerful, and definitely adds to the body of knowledge that points to a hardwiring of homosexuality
““That was the whole point of the study, to show parameters that differ, but which couldn’t be altered by learning or cognitive processes,” says Savic.””
My apologies, too, because the above quote has a few pieces taken from BTB
LOL, the software ate some mathematic symbols.
I meant: “Hormones” is the necessary and sufficient condition for “Aggressiveness”.
Test:
An by “above quote”, I am referring to post 108702
Evan,
There are some studies with humans that have shown that aggression can be associated with lower IQs as well - proving once again that humans tend to be a bit more complex than the rest of the animal kingdom in many ways, which makes it difficult and messy to make direct connections between other animal studies and humans. Hormones are definitely not the only thing affecting aggression and I wonder if maybe, at times anyway, we are talking about assertiveness - which isn’t the same thing
Jayhuck,
I used to write most of the stuff for my job in English (it was mostly on political and economic problems). But I still think it’s not as good as you think. Maybe it’s more technical. I’ve seen people from the office writing better than me. But thanks for the encouragement.
You are welcome Evan
Jayhuck,
Aggressiveness can be expressed in all our actions: writing, eating, opening beer bottles, breaking wood logs, dancing, playing soccer, even in choice of clothes or possessions that represent a more or less aggressive type of person. It’s probably the most pervasive basic dimension of animal being, that’s why it’s so strongly correlated with another critical behaviour: sex and reproduction. Aggressive behaviour that is socially disruptive or produces self-harm is a different problem, caused by other factors that fail to keep it in check (like disregulation of the ventromedial prefrontal cortex).
I don’t believe that the gay lifestyle is a good one, but still I’ve long felt that there were some in-built predispositional tendencies (whether genetic or hormonal)–but that these tendencies are not DETERMINATIVE (this is an important concept).
Think about it: How likely is it that the strong, silent type of man is likely to be gay? We tend to think of gay men as being very talkative, conversational, free and comfortable discussing their feelings, etc. If such personality characteristics are in-built and do not arise entirely from environment, then one can see that it may be that certain preconditions are necessary for a person to experience same-sex attractions. Still, necessary does not equate to determinative.
An analogy: It may be that only countries with a lot of conformity could ever “support” a dictator like Hitler. Conversely, an extremely individualisitic country such as the U.S. arguably might never unite around one dictator. Still, this doesn’t mean that all countries which stress conformity will be ruled one day by a Hitler-like figure.
I’ve had same-sex attractions. When I was in my early twenties they were especially strong. As I’ve aged I seem to be less attracted to men. And though I don’t “rubberneck” at women passing by, I can be attracted to their bodies with some focusing (no, not even an extreme amount). I notice that my level of same-sex attraction changes by the day. When I feel good about myself (masculine-wise), I’m not as attracted to men. When I feel that I’m not masculine and when I’m around someone who is, I start out feeling lousy about myself and end (because of how “unimportant” I feel I look in comparison) and then I sometimes end up feeling sexual feelings of attraction.
In general I never feel attracted to a man I feel looks less masculine than I do.
I am not the strong, silent type of person. I’m more talkative and “in-touch” with my emotions. My brother is extremely heterosexual. He’s absolutely the opposite. Cold. Not sensitive. Not as caring about what other people think of him. I think he could also have a propensity toward aggressiveness and possessiveness in relationships, though because he was raised well he has never hit a woman, etc. (though he has treated them poorly before).
He needs to grow and learn and become something better than he is now, and so do I. We each have our weak spots.
For me, the thought of pairing up socially with a man is not pleasant. I do have some typical feelings of wanting to be an alpha male type of man (one reason I become so flustered/frustrated/and then attracted around those who seem more alpha-male-ish than I am). Socially, I just don’t think same sex relationships would work at all. This is the situation I find myself in. That’s life.
The dream that some homosexuals have of having as satisfying of a relationship as a good heterosexual relationship is just a dream–a fantasy. I hope too many people with same-sex attraction don’t learn this after too many years walking down a dead-end street.
Jayhuck,
Women take a longer time to get into arousal. Men have a more prompt response to what is attractive (has all the good features) and impressive (provides some emotional relief that titillates one’s fantasising and arousal). But it was just a way of saying that “attraction” and “attractive” are simple words that name something that is more layered than we think. It’s not enough that the person be attractive — this can probably be noticed by anyone equally. It’s something else that creates that emotional protuberance that sparks arousal. My conjecture was that it must have to do both with spatial orientation and aggressiveness and how they filter visual stimuli to influence social recognition and project the ensuing reactions.
jayhuck
In one sense I see what you mean. How the heck could a bug be pretty much everywhere and why should we even guess that it might impact the brain?
Unfortunately herpes, rhino virus, flu virus and a thousand other things exist in every human community.
And there are NUMEROUS examples of these pathogens affecting human perception and behavior.
Example:
Flu virus causes roughly 20% of Schizophrnenia and Schiz impacts around 1% of the world population. OUCH!
So unforunately for all uf us, common germs can change the way we perceive things, and they do it all over the world. Whether you are gay, straight or inbetween you can bet germs have visited your brain and played some mischief with how it works.
Evan
I remember reading about that and it’s common. You can bet that’s not genetics, it’s environment. 1% of the people with a lifelong disinterest in sex is WAY to common to be genetic.
Female infertility is more common than 1%, in some communities it’s over 10%. But that’s not genetics, that’s pathogens and in most cases STDs.
Could we possibly dispense with the term “the gay lifestyle”? Its old and means absolutely nothing - there are all kinds of gay people living all different kinds of ways.
Drowssap - I meant that the chances of a big being in just about every culture and impacting the population in almost exactly the same way as others, is highly unlikely. Ouch
Evan - I think you are, at times, confusing aggressiveness with being assertive - again, two different things
big = bug
Evan,
“My conjecture was that it must have to do both with spatial orientation and aggressiveness and how they filter visual stimuli to influence social recognition and project the ensuing reactions.”
I apologize upfront for the sarcasm, but you mean to say that arousal has something to do with the way people “present themselves” and how we view these people? Astonishing
:) - I DO understand you were trying to be more specific 
Let me rephrase that, 1% of MEN with a lifelong disinterest in sex is WAY to common to be genetic. Women don’t need a strong sex drive to get pregnant once a year. Men however won’t be competitive without a strong sex drive. Any common genes that gave men a low sex drive were bushwhacked by natural selection a long time ago.
Example:
If a young man goes to a doctor and mentions he has a low sex drive the doctor will immediately assume something is wrong.
Jayhuck
I must admit that is one weakness in the theory. It’s not a deal killer because certain things DO work the same in people everywhere. However, you are right. It’s certainly curious.
Evan,
My main point about aggression is that you cannot look at aggression in other species of animals and directly make comparisons of that to humans. There ARE things we can learn about ourselves from watching the aggressiveness of other species, but its most definitely not the whole, or most of the, story when it comes to people.
You’re right - its not a deal killer, but I’d agree its curious
Evan
I read the article on PLoS ONE:
It was one, giant algebra equation. I think they need to find a gene before they suggest it might theoretically exist with a series of equations.
Drowssap -
“If a young man goes to a doctor and mentions he has a low sex drive the doctor will immediately assume something is wrong.”
That may be true Drowssap, but to a greater or lesser degree, that involves socialization and stereotypes - it involves expectations that are often taught us.
Many women do have high sex drives, and many men have low sex drives - some women sleep around, many men don’t. We don’t live in a world where a strong sex-drive in a man is needed anymore. In fact, promiscuity is something frowned on, and even punished, in many cultures - to what degree are we causing a change in that genetic predisposition? I often wonder just how much society can influence and shape our genome.
Jayhuck,
The conclusion is more balanced and cautious than “yep, it’s hardwired”. Some detected asymmetry at birth, some didn’t. Then they emphasise the effects of maturation and environment. They also left the door open for possible orientation-specific effects.
They also mention that the same male asymmetry effect that was observed in model animals is “established, in part, by early androgen exposure.” So, as I said, it must be hormones, but it seems it’s not all of it.
Evan,
It definitely is more balanced and cautious - and cannot state unequivocally that it is hardwired, but it adds to an ever-increasing and impressive body of knowledge that points to the fact that part of sexuality, perhaps even a large part, is definitely hard-wired. The distinctions in brain symmetry alone are incredibly interesting. The studies authors were smart enough as well to narrow down those aspects of the brain likely “to have been fixed at birth” - And hormones are made by genes. Which brings us back to genetics.
Jayhuck,
You have to decide: if it’s mostly inborn, then it’s not the result of experience or human alterations, therefore it’s animal. Therefore it must have correspondents in nature. Are you arguing for some unique etiology for an animal instinct in humans?
Evan,
I was only speaking to your use of the word aggression and the examples you gave of this attribute in nature - nothing more
jayhuck
For sure. There is a whole range of expected behaviors and a HUGE overlap. It only become interesting when somebody has a lifelong low or no interest. Or maybe on the other side hyper interest in sex.
Actually, even that’s not super interesting because genes could be responsible for just about anything in small numbers. It’s really only scientifically interesting when you find LARGE numbers of people with no sex drive or hyper sex drive or whatever. If 1% of a population had no interest in sex that’s pretty darned interesting.
It only become interesting when somebody has a lifelong low or no interest. Or maybe on the other side hyper interest in sex.
I agree
Jayhuck,
Nope. Assertiveness is a trait. Less assertive people can learn assertive skills but they can’t become more aggressive because of that.
Absolutely Evan
But its easy to confuse the two, and is often done.
Evan,
My issue with your use of the term began with this quote:
Aggressiveness can be expressed in all our actions: writing, eating, opening beer bottles, breaking wood logs, dancing, playing soccer, even in choice of clothes or possessions that represent a more or less aggressive type of person.
That’s not completely true - several of these things could simply be due to assertiveness, NOT aggression
That was my only point. 
I see the possibility of assertiveness being expressed in some of these instances more than I do aggression
Yes, and this is as personal and mysterious as anything can get - I can only relate it to curiosity of that which we don’t understand or that which we find different.
Ann,
There’s a great deal to be said for mystery
I think women just have a better way of composing and disciplining themselves to those people we find attractive and the thoughts we attach to it.
Ann,
I think, in many ways, women, at least in this country, are just more mature at times when it comes to this issue
There’s a great deal to be said for mystery
Jayhuck,
Unless it is detrimental, I don’t want to figure it out -
Well, yes, I would definitely have to agree with you. I see a distinct difference between genders on this issue and how it is handled.
Gay marriages started in California today, didn’t they? I’ve been so busy I had forgotten today was the day.
Today was the official day - they started granting licenses yesterday after 5p.m.
I completed the You Tube discussion (very long, very informative) and no longer doubt that what I have been experience in my life over the past 4-5 years with regards to change is real. This discussion was very helpful and I now feel I can move forward in peace and be extremely grateful for my religious upbringiing for helping me stay on this path long enough to truly experience the truth.
Dave G said: “Prepubescent children are attracted to one another, but it’s not sexual nor gender-specific.”
Again, where does Dave G. come up with this stuff? My homosexual attractions were there as early as first grade and they were definitely sexual and gender specific. Dave G.’s theory that gays are “pushed into it” or “want it” or are gay because the “practice” it has little to do with the REALITY of what gays actually experience.
Is Dave G. Gay? Does he know any gay people? Has he really talked with them and listened to the stories of their lives? Did he get pushed ihnto his orientation? Did he want it?
Michael Bussee
Ok, I think I’ve said this before but I am a stereotypical, nerdy straight gay. I’m curious about this so maybe it’s time to exchange some notes.
Many people mention that their “sex attractions” didn’t start until puberty. That was not my experience, and apparently it wasn’t yours either. I knew something was “special” about adult women even before I started kindergarten. I didn’t know what it meant, but pretty adult females made my heart flutter. And when I talked to girls my age it was exciting in a weird way. Of course this was completely at odds with my other feeling that all girls were stupid and evil.
When I hit puberty those feelings went into overdrive. I remember to this day my first real attraction. A girl that I thought was cute sat across from me in the 8th grade. I think I was 12 years old. One day she leaned over and I saw partially down her shirt. My heart felt like it shot through my neck.
Ok, I think I’ve said this before but I am a stereotypical, nerdy straight gay
Drowssap,
Do you mean “guy”?
My first was a kid named Tommy. A real first crush — in first grade. I was attracted to him on all levels. Specifically. Sexually. Lots of the gay men I have talked to report similar feelings. I imagine lots of straights do too.
It had nothibng to do with “wanting” to be gay. I didn’t want it. It had nothing to do with “practicing” it, I didn’t practice it. It had nothing to do with choosing it. It was not a choice. No one would seriously argue that straights are straight because they want to be, choose to be or get that way by “practice”.
We have to be careful not to force reality to fit our theories and preconceptions. That is why I would strongly encourage Dave G. to really listen to gay people and not just say what he wants to believe about us. Really listen to the experience of being gay.
Michael,
When you say “sexually”, did you know about sex at that age or how could you describe what you felt that connected sex with it.
Ann
SWEET HAYSUS!!!
Yes I did Ann. I meant GUY!
I don’t know how to answer that. I didn’t know what sex was but the feelings were definitely and specifically sexual — sex didn’t get “connected” with it. Sex was part of the whole.
Michael Bussee
I find that interesting. For me it wasn’t sexual. When I looked at women I had no thoughts of actual sex. I didn’t even know what that was until I was much older. Women were just exciting to look at. Girls became truly “sexual” about highschool age.
I have no doubt you are 100% correct on that. I didn’t pick “straightness” straightness picked me. In fact when I grew up in the 80s I didn’t believe people could be anything BUT straight. When it’s the only thing you ever knew and all the gay people are in the closet you can’t believe it’s actually out there. I was probably in college before I realized there really were gay people in the world and they were genuinely put together different. Even then I thought it must have something to do with personality, not biology. One of my friends told me that all gay people were molested as kids and I halfway believed that for a long time. It wasn’t until maybe 5 years ago I started to believe it was significantly biological.
Drowssap,
It seems that whatever it was or whenever it was, or whoever we connected it with, our first “feeling” of a crush or sexual stimulation or attraction have been deeply personal. This is why I think we need to also look at and respect the individual story rather than the collective ones. Some people connect early observations of smell to who sparked their interest. Why are some people physically attracted to only those of a particular race or foreign culture than their own? Does that start at an early age? Whatever it is, it obviously was something that made us feel good and we wanted to experience more of it. What made us feel good could also have a lot to do with our circumstances at the time. A little girl could feel great comfort being around another girl and that could develop into a dependence. I think it was Concerned who wisely said - for some, SSA can provide a welcomed distraction to otherwise stressful situations the child or adult is feeling. When the realizaion of shame takes hold, through limited level of understanding, a child is going to keep all this to themselves and IMHO, this can, and of itself, manifest into a perception and perspective of themselves that might or might not be true if they could have caring and loving intervention from a parent. The term “arrested development” is interesting if those first feelings stay with us as a guiding force and determine, consiously or subconsciously, the direction we go in.
Drowssap: I am trying not to get too graphic here, but I was attracted to and fascinated by the specifics and totality of male antatomy. I had no such attraction or fascination towards women — quite the opposite. That has remained constant throughout my life. At age six, the urges and feelings were definitely sexual.
I didn’t understand what adult sex was or even what “sex” was — but I knew what excited me, what attracted my attention, what I wanted to experience. And no, I was never molested. These sexual feelings emerged in my awareness just I I imagine they must for straight people.
I knew what excited me, what attracted my attention, what I wanted to experience
I was attracted to and fascinated by the specifics and totality of male antatomy
Michael,
Was there any emotional connection you felt to him or was it just the anatomy that attracted you to him and desired to experience? Do you remember why him and not another little boy?
Michael,
Your personal story is very interesting. I gather that when you were attracted to boys they were not your playmates at that time.
I remember that was the case for me in kindergarten. My mind was captivated by two girls: one was a brunette lively girl named Lydia, the other was a shy blonde girl named Gina. I never played with them, I don’t remember why, I was busy doing something else, but they were always in the distance. I was thinking about them even when I was at home. There was also this girl who was one year older than me, whose parents were friends with my parents. Whenever we all met I did not understand why they were making fun of me that I should do something to her. I was a bit ashamed, I think, that they spotted me because I liked her.
When I went to school, the story got more intense. I developed a years-long attraction for a brunette girl. One day we were supposed to be grouped in pairs for doing some outdoors stuff. The teacher paired me with her. I was hardly focusing on doing anything else but holding her hand. My heart was pounding like I was flying an helicopter by myself for the first time, hundreds of metres above a cascade. When I went home, I was looking at my hand and couldn’t believe it. OK, I admit it, I couldn’t wash my right hand for one day.
Ann
I think you are correct. Socialization or a unique set of social circumstances could certainly turn and otherwise straight person gay. How many people fall into this category is the $2 question. I don’t think this is a LOT of people but it’s some for sure.
Michael Bussee
In my specific case it was always the general curviness of a woman’s body and the attractiveness of her face.
I was chatting in another “humor” blog about a year ago and I posted a picture of a particularly natural, attractive bikini model and asked if any gay men found her attractive. This girl is so gorgeous that any straight guy would melt in her presence. Predictably every gay man who responded said they felt nothing at all, ZERO!
I know it sounds crazy but straight guys brains aren’t organized to comprehend this. I think that’s one of the reasons that for so many years straight guys thought that gay guys could just, “go straight.”
“You see the same beautiful girl that I do and obviously you are attracted to her too, right?” (baffled questiong look)
And then there is the other side of the coin, hehe. When we see photos of half naked men that have sexually suggestive expressions on their faces it makes us want to squirt bleach in our eyes.
I don’t think that response is entirely learned. The feeling is so instant and bad that all guys find it humerous when it happens to another guy. When I go to Boxturtle and those banner ads are up I try to squint my eyes so I don’t have to see them. 
Evan
Without saying the country you that live can you mention the region?
West, East, South?
Drowssap,
I was born in a country from the Eastern part of Europe and grew up there during the Communist era. After that I moved to the Western part of Europe and lived and worked in a couple of countries there. Now I’m back in my country, but will probably have to leave again, because of my job.
Evan
Eastern Europe cool. I read the other day that during WW2 a large number of German soldiers stationed in Poland deserted rather than be shipped out of the country because the women were so attractive.
Drowssap,
Man, Polish and Czechish women are incredibly beautiful! Hungarian ones too.
Evan
I’m happily married for 13 years but if anything happens to my wife I’m going to get a mail-order bride from over there.
Drowssap,
I don’t know, man. I’ve seen a few Philippinas that could change your mind.
I guess that’s why exotic becomes erotic.
Evan and Drowssap,
I think the Beach Boys had it right when they said said where the prettiest girls in the world were
Ok, back on topic - regarding this study, what is going to be done with these findings? While they are interesting and can certainly lead to other findings, what and where does that take human behavior, especially for those who want to following the teachings of their faith?
I was thinking about what could cause attractions so early in life, but it doesn’t seem to be the EBE story completely.
For example:
When I grew up, the boys were not divided in typically aggressive and atypically aggressive groups (or boys who mainly played with girls). There were very few who were unusually aggressive and were seen as bullies or problem children, but the rest gravitated in the general middle. The play activities were mostly gender-specific because we liked to play soccer (European football) and other football games, but it was not unusual to sometimes organise mixed games. But during kindergarten or early school each boy would have probably felt awkward playing with a girl, because we did not know much about what girls did or liked. They were from another planet, but I don’t know what made us think that way, because some of us got sisters. There was never any pressure from anyone to only play in gender groups or to marginalise some kid because he/she was atypical. I don’t remember that. I’ve never seen one case like that during childhood. There were a few kids who were priviledged, because their parents were better off, and they rarely played with us, but that was all.
That’s why I think there is something important missing from Daryl Bem’s theory, something like a very basic construct that is both determined by brain configuration and early interaction. It’s not restricted to aggressiveness or temperamental dimensions, although it must be influenced by them. There must be an inner body image that is constantly adjusted according to those factors and the interaction with the environment. So when a child interacts with others, according to his rhythm, he also adjusts these inner body representations of himself and others. Maybe these internal body images are also determined by the hormonised brain, so the children identify with others or interact with them based on how these particular maps are projected with the associated feelings and sensations.
This is the only way that we can theoretically resolve the temporally different dynamics of development that lead to similar results. It does not seem to simply reduce to aggressiveness-plus-temperamental-factors and socialisation patterns, because these are not strongly polarised inside gender categories, but rather uniformly distributed. We’re not talking about little hormonal-genetic robots that followed a pre-determined path. Generalisable factors must combine with an inner construct that evolves under their influence but also according to a personal tangle of experiences.
That’s why I think we now are in the middle of a deterministic scientific fashion, that aims to narrow down the search to mechanistic models of sexual orientation, but after this period will be consumed, we will probably return to experiential factors and how they combine with predispositions to develop an individual brain map of genders and to work with it in everyday life interactions. That brain map containing the gendered representations of bodies must have been shaped by past predispositions and past experiences and put to work by present levels of aggressiveness and temperamental dimensions stemming from fluctuating genetic expressions.
I call that Hypothesis No 3.
Ann
The findings of these two studies will have a HUGE impact going forward.
SSA appears to be strongly environmental… but not SOCIALIZATION!
That’s not exactly how many Conservative Christians thought this would end up. But it’s also not that far off because it still comes down to environment. A good number of environmental possibilities (but not all) are things that go wrong. If something is going wrong we should know. On the flip side if SSA is the result of something working just fine we should know that too.
Conservative Christians have endless supplies of money, motivation and brainpower. They could put together more research dollars in 1 week than the entire sum of money ever spent on SSA. Christians could readily take charge of this situation and become key players in solving the mystery of SSA. Every single day I hope they do.
There’s also another important aspect: this study must not only be replicated, but also duplicated in order to have these patterns confirmed.
Hi Warren!
My own conclusions, and the evidence that led me to them, is on my blog, the post BiGender and the Brain
I also want to bring here for debate the findings from another study by Ponseti et al (2007) that ‘Homosexual Women Have Less Grey Matter in Perirhinal Cortex than Heterosexual Women‘. The conclusions from the Savic study should, if valid, factor in those results to reflect the patterns of androgenisation that were found in homosexual women. Relevant quotes: