Lesbian and putative pheromone study, Part 5 – AP says they were wrong

May 14, 2006 By Warren Throckmorton

On Friday afternoon, May 12, the AP issued a “clarification” of their report covering the study of the brains of lesbians. Here is the statement:

Clarification: Lesbian Brains Story
Fri May 12, 2:36 PM ET

WASHINGTON – In a story May 8, The Associated Press reported on the perceptions of lesbian women and heterosexual men and women when sniffing chemicals derived from human hormones. That report was based on a chart in a research study which indicated different perceptions of the chemicals, such as pleasantness, familiarity and irritability.

While there were differences in how the brains of homosexual and heterosexual participants reacted to the chemicals, the story should also have included the conclusion that indicated differences in individual perceptions were not statistically significant.

I made a request to the AP Thursday afternoon for the original AP story to be reviewed by the Science editor. Then, at the request of the AP, I supplied all of the correspondence between Dr. Ivanka Savic, Randolph Schmid and me. I have heard nothing directly from the AP as yet.

This is an important correction because many were misinterpreting the study thinking that lesbians responded differently in their feelings to the different smells. No such differences were reported, nor did any of the gay or straight participants experience sexual arousal in response to the substances inhaled. The study authors, lead by Ivanka Savic, have been clear all along that they do not know what the brain differences mean. No one knows how these differences would directly relate, if at all, to chosen sexual behavior.

So the correction did not go far enough. About the Savic study, the original story said: “It’s a finding that adds weight to the idea that homosexuality has a physical underpinning and is not learned behavior.” As Dr. Savic stated, “This is incorrect and not stated in the paper.” Since the study did not explore learning factors, one cannot state that the study adds weight to any ideas about learning and sexual feelings or behavior.

The website GayNZ came closer to an accurate correction, reporting:

AP says lesbian brains story was wrong

The Associated Press has clarified a story they released which inferred that lesbian brains are significantly different to those of heterosexuals.

The story was released on May 8 and carried by GayNZ.com on May 9 (â€œLesbian brains react differentlyâ€). The story cited Swedish research that showed lesbians are more likely to find male pheromones, essentially the scent of men, more irritating, and furthermore that lesbians processed both male and female hormones in the â€˜scent areaâ€™ of the brain, whereas heterosexuals processed the pheromone of the opposite sex in the hypothalamus, or â€˜sexual stimulationâ€™ area of the brain.

The report prompted a number of sexuality-researchers to claim that this revealed that sexuality is biologically formed, rather than solely through life experiences.

The Associated Press now claims this conclusion to be unsupported by the research, as no statistically significant differences were found. Most researchers continue to maintain that the formation of sexuality is a complex issue, stemming from both biological and cultural factors â€“ or, simply put, both nature and nurture.

The state of the art is much closer to this statement from GayNZ than the article from the AP.

(Thanks to Colleen Keating for the tip.)

Lesbian and putative pheromone study, Part 4

May 10, 2006 By Warren Throckmorton

Much correspondence has gone on regarding this study and the way it has been reported by the Associated Press. I can say this: the Associated Press writer, Randolph Schmid, has been made aware that the new study says nothing about whether sexual behavior is learned. Here is a quote from a recent email from Dr. Savic: “The easiest way to clarify the situation is to go to the original data. I do therefore refer to the manuscript in PNAS. The study does not give answer to the cause-effect issue. Sincerely, Ivanka Savic”

She also pointed out other flaws in the AP report. For instance, this section is misleading:

“Heterosexual women found the male and female pheromones about equally pleasant, while straight men and lesbians liked the female pheromone more than the male one. Men and lesbians also found the male hormone more irritating than the female one, while straight women were more likely to be irritated by the female hormone than the male one.All three groups rated the male hormone more familiar than the female one. Straight women found both hormones about equal in intensity, while lesbians and straight men found the male hormone more intense than the female one.”

To this, Dr. Savic said: “…the perception of these compounds was similar in ALL the subjects and all statements [in the AP article] about the pleasantness, irritability etc. are erroneous.”

In fairness to Mr. Schmid, the graph in the article gives the impression of differences but in statistical terms, the differences were small enough that they cannot be considered signficant. The AP report gives the impression that there were more sexual preference related differences than were actually found.

So we have this situation: the AP writer knows the study author has found significant errors in the story. She even asked if they could be corrected and to date there has been no correction. Perhaps one is in the works. Corrections are issued all the time, I wonder why this story is different.

I do not take interest in this just to be difficult. I think the media have a great responsibility in this climate to report accurately. And saying that “the findings add weight to the idea that homosexuality…is not learned behavior” is not accurate reporting. The other factual errors just add weight to the idea that a correction is in order.

Lesbians and pheromones, Part 3. Healthday.com article

May 9, 2006 By Warren Throckmorton

Yours truly was quoted in a HealthDay article by Kathleen Doheny. This piece sticks much closer to the actual report than the AP article does.

Lesbians and pheromones, Part 2. Email from Ivanka Savic

May 8, 2006 By Warren Throckmorton

Here is an email I sent to Dr. Ivanka Savic today about the study of lesbians’ response to putative pheromones. My note is in italics and Dr. Savic’s reply is in bold letters.

Dr. Savic:
The Associated Press story came out today about your study and I think they have reported it incorrectly.

First I am wondering if you can help me understand things more clearly. I am enclosing a link to the AP report: http://www.forbes.com/entrepreneurs/feeds/ap/2006/05/08/ap2729698.html

First, in the report the reporter writes: “It’s a finding that adds weight to the idea that homosexuality has a physical underpinning and is not learned behavior.”

THIS IS INCORRECT AND NOT STATED IN THE PAPER

As I understand your article in PNAS, you specifically offer learning as a hypothesis for your findings. Isn’t this true? I believe the reporter is misleading on that point.

THIS IS VERY UNFORTUNATE; AND YOU ARE ABSOLUTELY RIGHT

Second, the AP report says: “In lesbians, both male and female hormones were processed the same, in the basic odor processing circuits, Savic and her team reported.” I understand that the study did show that AND (male condition) was processed akin to other odors by lesbians. But wasn’t there also some hypothalamic processing of EST (female condition) by lesbians?

YES! AND ALSO CONJUNCTIONAL ANALYSIS SHOWED A COMMON HYPOTHALAMIC CLUSTER IN THE HYPOTHALAMUS:

It was weaker and apparently not in the anterior hypothalamus but didn’t you also find dorsomedial and paraventricular hypothalamic activation? So it would be inaccurate, would it not, to say “both male and female hormones were processed the same?”

YOU ARE FULLY CORRECT

THANK YOU VERY MUCH. HOW DO I ACCESS THE AP REPORT??

Ivanka Savic

ADDENDUM: Someone posted and asked why I changed the AP wording when I wrote to Dr. Savic. I did not change it but it appears the AP did from saying homosexuality had a “physical underpinning” to a “physical basis.”

Lesbians and pheromones

May 8, 2006 By Warren Throckmorton

News is starting to leak out about an article embargoed until 5PM today. The article reports a study by the same Swedish team that did the gay male and pheromone study about a year ago. This study shows that sexual orientation at the extreme (5-6 Kinsey scale) differentiates how the brain responds to a putative pheromone. The response from lesbians is not as clear cut as gay males. Lesbians process estrogen derived pheromones both in the normal olfactory fashion and via the hypothalamus (a link in the sexual response). The participants did not experience any sexual response so it is interesting that these lesbians’ brains registered the pheromones in a different way than did straight women. Lesbians were somewhat like straight men but not exactly like them. The reference is: Berglund, H., Lindstro”m, P., & Savic, I. (2006). Brain response to putative pheromones in lesbian women. Proceedings of the Natural Academy of Science, Early Edition (www.pnas.org).

As usual, Gay 365 has it wrong. Their article says: “It’s a finding that adds weight to the idea that homosexuality has a physical underpinning and is not learned behavior.” The study doesn’t say anything about how the brain responses occurred. In fact, the study suggests that the differing responses may indeed be learned.

I proposed to Dr. Savic that the team consider an additional study of bisexuals and ex-gays. Dr. Savic replied favorably that the team would consider it.

Addendum: My apologies to Gay 365, they took their info from the AP story. Here is what Dr. Savic said about learning in a New Scientist article on the subject: “But our study can’t answer questions of cause and effect,” cautions lead researcher Ivanka Savic at the Karolinska Institute in Stockholm, Sweden. “We can’t say whether the differences are because of pre-existing differences in their brains, or if past sexual experiences have conditioned their brains to respond differently.”

Sexual identity: Our bodies tell us who we are

June 13, 2011 By Warren Throckmorton

(First posted October 1, 2007)

Warning: Long post…

This post could be part three of the series on sexual identity therapy and neutrality but I chose this title because I want to focus on one specific issue, at least in my mind, with telling psychotherapy clients that “our bodies tell us who we are.” Saying something like this to a client is the expression of a natural law argument that is expressed by Dr. Joseph Nicolosi in his article “Why I Am Not a Neutral Therapist.”

Our Bodies Tell Us Who We Are

Philosophically, I am an essentialist — not a social constructionist: I believe that gender identity and sexual orientation are grounded in biological reality. The body tells us who we are, and we cannot “construct” — assemble or disassemble — a different reality in which gender and sexual identity are out of synchrony with biology.

The belief that humanity is designed for heterosexuality has been shaped by age-old religious and cultural forces, which must be respected as a welcome aspect of intellectual diversity. Our belief is not a “phobia” or pathological fear.

Natural-law philosophy says this view derives from mankind’s collective, intuitive knowledge; a sort of natural, instinctive conscience. This would explain why so many people — even the nonreligious — sense that a gay identity is a false construct.

Clients who already believe a natural law argument would most likely look for a therapist who believed as Dr. Nicolosi does. In that case, I do not see how he could be accused of imposing his values on the client; clients who are committed to this perspective (many conservatives, for example) might not work well with a therapist who did not articulate a similar view. On the worldview front, I suspect many people are directed by their spiritual advisors to look for counselors who are amenable to the teaching of their church. I also suspect, that feminists look for feminist therapists and so on. This will no doubt continue no matter what the professions pronounce.

What I want to raise now are some issues with the natural law argument. Specifically, I propose that if we know who we are via our bodies, then a fairly solid argument can be made against Dr. Nicolosi’s conclusions. He argues that genitalia and procreative capacity is the definer of correct identity. However, there is more to body than genitals and secondary sex characteristics. Brain is a part of body. As an organ of the body, the way the brain functions and is organized must be important as well. I am not here talking about psychological constructionism or the constructed opinion of a person that he/she is gay or straight, male or female. I am talking about the automatic response of the brain to triggers both sexual and otherwise that differentiate gay and straight people. In the research available, brain reactions differentiate people based on sexual preferences. In other words, if the body tells us who we are, and brain is body, then our brains tell us whether we like the same sex, the opposite one, or both. And our brains do this well before we have time to think about it.

I have written before about the pheromone studies conducted by a team led by Ivanka Savic from Sweden. Here is what I wrote about their study of lesbians:

This study shows that sexual orientation at the extreme (5-6 Kinsey scale) differentiates how the brain responds to a putative pheromone. The response from lesbians is not as clear cut as gay males. Lesbians process estrogen derived pheromones both in the normal olfactory fashion and via the hypothalamus (a link in the sexual response). The participants did not experience any sexual response so it is interesting that these lesbians’ brains registered the pheromones in a different way than did straight women. Lesbians were somewhat like straight men but not exactly like them. The reference is: Berglund, H., Lindstro”m, P., & Savic, I. (2006). Brain response to putative pheromones in lesbian women. Proceedings of the Natural Academy of Science, Early Edition (www.pnas.org).

I also reviewed their initial study of males:

• The study does show involuntary hypothalamic response associated with self-assessed sexual orientation

• The study shows that gay males do react to the estrogen condition but in a different manner than they react to the testosterone condition

• The study cannot shed light on the complicated question of whether sexual orientation of the participants is hard wired.

• The brains of these participants may have acquired a sexual response to these chemicals as the result of past sexual experience. In other word, the response described in this study could well have been learned.

• If these results hold up, this could explain why varying sexual attractions seem so “natural.” Also, such conditioning could give insight into why changing sexual attractions is often experienced by those changing sexual preferences as a process of unlearning responses to environmental triggers.

There are other lines of research that also find large involuntary differences in brain response or perceptual response associated with sexual attractions. I could add the brain imaging work of Michael Bailey which I referenced recently.

(more…)

Reparative therapy information

April 22, 2009 By Warren Throckmorton

I have done several articles and numerous posts on reparative drive theory and related issues. This page serves to bring those together in one place. The format for now will provide the link and a brief explanation of the post or article.

I Am Not a Reparative Therapist – This article was controversial at the time and is a good starting point to understand some of my concerns about reparative drive theory and related therapy.

Sometimes I am referred to as a reparative therapist which is inaccurate. I recently made that even clearer with this article published on Crosswalk.com and elsewhere which questions the theory’s helpfulness in counseling and ministry.

Research and reparative drive theory

Within the psychoanalytic tradition, several views of homosexual etiology have been proposed. As noted here, Freud believed homosexuality was a developmental arrest. However, he did not think change was likely nor psychologically necessary. If a boy did not identify with father as a resolution to the Oedipal drama, he would likely identify with mother thus preferring males as sexual objects. Some later psychoanalytic writers have looked to the mother-son relationship as crucial (would the son develop an engulfment phobia surrounding women because of mom), whereas others, such as the reparative drive theorists have put the focus on father (if the father and son do not bond well, then the boy will seek to reconnect with masculinity via homosexual attraction/behavior). Joseph Nicolosi tells fathers, “If you don’t hug your son, some other man will.”

A focus on the mother and the father is common in reparative drive theory and is referred to as the “classic triadic model.” This means that reparative therapist believe the family structure which is common to homosexual males is a too-close, smother-mother and a distant or hostile father who ridicules, diminishes or ignores the son’s developing masculinity.

Direct tests of the reparative drive theory

I have privately and publicly asked proponents of reparative drive theory for the three best studies which support the theory. The most frequent response I have gotten is the Bieber et al (1963) study and to review the book by Fisher and Greenberg (1996).

In this 2007 post (Psychoanalytic theory and the etiology of homosexuality: What does research say?), I review what Fisher and Greenberg found in their examination of research on cause. About the research they said:

The post-1977 material we have reviewed concerning male homosexuality has narrowed the apparent support for Freud’s formulation in this area. Previously, we regarded the empirical data to be congruent with with Freud’s theory that male homosexuality derives from too much closeness to mother and a distant negative relationship with father. As noted, the increased pool of data available reinforces the concept of the negative father but fails to support the idea of the overly close, seductive mother…So we are left with only one of the major elements in Freud’s original formula concerning the parental vectors that are involved in moving a male child toward homosexuality. This reduction in confirmed points on the graph makes it all too easy to conjure up alternative theories of homosexuality that could incorporate the “negative father” data…There would be no need to appeal to the Oedipal image of a son competing with his father for mother’s love.

Note that Greenberg and Fisher dismiss one corner of the classic triadic model. To these authors, who originally believed the research supported the model, the body of research between 1977-1995 did not support the classic model. Even though some studies (not all) found more negativity between fathers and homosexual sons that heterosexual sons, the explanation for this is not of necessity causal. In other words, the father-son relationship problems could have derived from the fact that the son disclosed homosexuality. Also, possible is the fact that the father perceived some difference in the son (related to developing homosexuality) which led to a rocky relationship.

I address Bieber et al briefly in the I Am Not a Reparative Therapist paper. I am working on a post which more directly critiques the study. There are many flaws in Bieber, namely, the sample of homosexuals were all clinical patients with personality disorders, schizophrenia, etc. Any attributions about homosexuality and their parenting would have to be confounded by the fact that home life of these people may have been troubling and contribute to the multiple problems that brought them to therapy. There are reasons from later research to believe that the group of people who seek therapy related to homosexuality is likely to have more troubling parent-child relationships than those who do not seek therapy.

Although Bieber believed he had proven the classic triad, 76 of Bieber’s 106 homosexual subjects did not fit the triadic pattern. A majority of men had some disturbance in the home but the typical pattern was not so typical.

Nottebaum et al. (2000) asked gay and participants in Exodus International ex-gay ministries if they had good relationships with their mothers and fathers while growing up. Generally, Exodus ministries promote the view that homosexuality is the result of the classic family triad. The gay male/lesbian participants described a significantly better relationship with parents than did the Exodus group. The Exodus males, more so than the females, said their parental relationships were poor.

Seutter and Rovers surveyed 130 heterosexual and 24 homosexual seminarians to examine differences in perceptions of parents. There were no difference between groups on maternal relationships and sense of being intimidated by their fathers. There was a moderate difference between groups on a dimension they called intimacy with father, with homosexually attracted participants feeling less intimate. Again, as in past studies, there was considerable overlap between gay and straight groups, with some gay seminarians feeling very close to their fathers and some straight men describing a lack of intimacy. Also, there was no check on which came first making it impossible to specify direction of causation.

Andrew Francis released a study in 2008 which demonstrated very little effect of parenting and family dynamics on sexual attraction or behavior. Reparative drive theory predicts that disrupted parenting and family should lead to more homosexuality. This study did not find that, rather:

Francis also examined family structure and found more trivial associations. For instance, he found a 3.8% increase in the likelihood of ever having a same-sex sexual partner among those who did not live with either parent. In contrast to reparative theory expectations, he reported that identifying as less than 100% heterosexual for males was associated with living with only dad. No romantic attraction or same-sex behavior was reported for males living with only mother.

There were other factors which Francis reported but the real take home point from this study is how little any of these variables predict sexual orientation. This study undermines reparative drive theory due to the unremarkable performance of the parental variables to predict orientation. One would expect to find great differences between male heterosexual participants and same-sex attracted participants if fathering/mothering were crucial to male sexual orientation as Joe Nicolosi teaches. In fact in this YouTube video, Nicolosi says that the main factor in the development of male homosexuality is a distant or hostile father.

The Francis article finds very little predictive power in family dynamics of any kind. There is no predictive power at all for those whose parents are separated. Living with dad should insulate against a homosexual outcome and living with mom alone should enhance the likelihood of same-sex attraction and/or behavior. In this sample, it does not.

Ivanka Savic introduced a series of studies which compromise the reparative drive notions. The first series demonstrating that brain responses to putative pheromones predict sexual orientation in men, and (somewhat less so) in women.

Sexual abuse and sexual orientation: A prospective study – Reparative therapy predicts that attachment disruptions set up a situation where the person seeks to repair the detachment from the same-sex gender parent with defensive longing. From this foundation, one would expect that abused and/or neglected children would be more likely to demonstrate homosexuality in some form. However, in this 2009 report by Widom and Wilson, this result did not show up. The authors knew the abuse and neglect histories of their participants and interviewed them about sexual behavior. They did find an association between male sexual abuse and later homosexual behavior, but it was not huge. They did not find a significant relationship between neglect and homosexuality. The authors noted:

These results were consistent for men and women and support the conclusions of Bell et al (1981) that early parenting experiences, positive or negative, play little direct role in the development of sexual orientation. Among women, we also found no associations between childhood sexual abuse and same-sex relationships.

Multiple factors involved in sexual orientation: New study – The authors of this study (Niklas Långström, Qazi Rahman, Eva Carlström & Paul Lichtenstein) provided this summary of results:

“The results show, that familial and public attitudes might be less important for our sexual behaviour than previously suggested”, says Associate Professor Niklas Långström, one of the involved researchers. “Instead, genetic factors and the individual’s unique biological and social environments play the biggest role. Studies like this are needed to improve our basic understanding of sexuality and to inform the public debate.”

Overall, the environment shared by twins (including familial and societal attitudes) explained 0-17% of the choice of sexual partner, genetic factors 18-39% and the unique environment 61-66%. The individual’s unique environment includes, for example, circumstances during pregnancy and childbirth, physical and psychological trauma (e.g., accidents, violence, and disease), peer groups, and sexual experiences.

This at first may sound promising for reparative theory advocates. However, while for some people unfavorable attachments could be relevant, the study indicated that there was no one set of environmental experiences which associated with homosexuality, as predicted by reparative theory. In fact, common family experiences of twins did not show up at all for men and only slightly for women.

Posts on the theory

Reparative therapy for females – Discounts Janelle Hallman’s thesis that lesbians do not have “selves.”

Father – Son estrangement – This brief post quotes research on father-son relationships in general and how that relates to the thesis that male homosexuals have poor relationships with their fathers. Straights have such poor relationships too.

Queer theories for the straight guise

Many people want to know why they experience same-sex attraction. Reparative drive theory provides a narrative but it may not be correct. In Why Do I Have These Feelings? I examine how this pressure for a narrative may be misleading.

Masculinity and reparative therapy

Mankind Project clarifies stance on reparative therapy – Reparative therapists often refer clients to activities and groups which promise to enhance masculinity as a means of reducing same-sex attractions. Macho Man group Mankind Project clarifies that the New Warriors Training Adventure is not a form of reparative therapy.

Sexual identity Therapy and Reparative Therapy

As I wrote here, sexual identity therapy and reparative therapy as described by Dr. Nicolosi are not compatible. Reparative therapy begins with the idea that homosexuality always derives from deficient childhood experiences and tells clients this theory. If the client does not buy it at first, the client eventually changes his mind or leaves therapy. In sexual identity therapy, clients are not given a narrative or a prescription and are provided with the totality of evidence regarding causation and change.

In Sexual identity therapy: Is neutrality a bad thing? I take up the approach of reparative therapists to impose a narrative about childhood experiences and present adjustment on clients.

Sexual identity therapy and neutrality, part one

Sexual identity therapy and neutrality, part two

Use of research

Confirmation bias is an issue for all who work in theoretical matters. Humans seek information which confirms previously held ideas and ignore or forget data which do not confirm our views. I have several posts where I have pointed this out with specific studies and topics.

In 2008, NARTH released a “fact sheet” regarding female homosexuality. I critiqued this paper in two parts. Part one was a general review of the paper and the misleading aspects of it. Part two, specifically examined claims regarding sexual abuse and female homosexuality.

NARTH Fact Sheet on Female Homosexual Development, Part One

NARTH Fact Sheet on Female Homosexual Development, Part Two – Child Sexual Abuse

Regarding the efficacy of reparative therapy, this post about NARTH’s use of Shidlo and Schroeder’s study of harm stands out. Facilitated by Neil Whitehead’s reanalyis of Shidlo and Schroeder’s work which did not reach statistical significance, reparative therapist and NARTH president, Julie Hamilton suggests that reparative therapy reduces suicidality. One may believe that but the Shidlo and Schroeder cannot be used to make that claim.

Lisa Diamond is well-respected research from the University of Utah who researches the sexuality of women, especially sexual fluidity. Her work is sometimes cited by NARTH as evidence for change. However, she believes they mislead people in the way they use it as I noted in a November, 2008 post.

Stay tuned for updates…

Study examines brain differences related to sexual orientation

June 17, 2008 By Warren Throckmorton

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, the researchers 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, studies of twins seems to demonstrate a role for a variety of environmental factors which operate differently for different people.

UPDATE: In the paragraph above, where I mention “environmental factors,” I am not referring to parenting and childhood trauma. I believe the research on these topics rule those factors out as general causes of homosexual development. For some very small number of people, particular women, those factors may lead to a kind of homosexual adaptation but I do not believe they lead to same sex attraction which occurs prior to any homosexual behavior.

The studies showing brain differences are compelling and indicate a lack of choice in sexual feelings and a spontaneous emergence of those feelings.