I posted 2 weeks ago about this twin study but it is now making the media.

Here is the abstract of the article from Archives of Sexual Behavior:

There is still uncertainty about the relative importance of genes and environments on human sexual orientation. One reason is that previous studies employed selfselected, opportunistic, or small population-based samples. We used data from a truly population-based 2005–2006 survey of all adult twins (20–47 years) in Sweden to conduct the largest twin study of same-sex sexual behavior attempted so far. We performed biometric modeling with data on any and total number of lifetime same-sex sexual partners, respectively. The analyses were conducted separately by sex. Twin resemblance was moderate for the 3,826 studied monozygotic and dizygotic same-sex twin pairs. Biometric modeling revealed that, in men, genetic effects explained .34–.39 of the variance, the shared environment .00, and the individual specific environment .61–.66 of the variance. Corresponding estimates among women were .18–.19 for genetic factors, .16–.17 for shared environmental, and 64–.66 for unique environmental factors. Although wide confidence intervals suggest cautious interpretation, the results are consistent with moderate, primarily genetic, familial effects, and moderate to large effects of the nonshared environment (social and biological)
on same-sex sexual behavior.

Reactions are mixed but not really along any ideological grounds that I can see. For instance, from ScienceNOW:

J. Michael Bailey, a psychologist at Northwestern University in Evanston, Illinois, who led earlier twin studies of sexual orientation, calls the new study “good, important, and one unlikely to be bettered in the near future.” But Jonathan Beckwith, a geneticist at Harvard Medical School in Boston, says that the new work fails to overcome a number of problems faced by previous twin studies. He notes that the final sample included only 12% of the males in the Swedish registry, leaving open the possibility of recruitment bias. And Beckwith says that the failure to control for family environment could inflate estimates of genetic influence.

Co-author Qazi Rahman, was quoted by the Washington Post:

“This study puts cold water on any concerns that we are looking for a single ‘gay gene’ or a single environmental variable which could be used to ’select out’ homosexuality — the factors which influence sexual orientation are complex. And we are not simply talking about homosexuality here — heterosexual behavior is also influenced by a mixture of genetic and environmental factors,” study co-author Dr. Qazi Rahman, a leading scientist on human sexual orientation, said in a prepared statement.

I intend to devote at least one more post to this study as I agree with Michael Bailey that it is an important study. I think along with the other 2 population based studies (Bailey’s in 2000 and Kendler’s also in 2000), it provides a picture of modest genetic effects along with a major role for non-shared enviromental factors. Many roads lead to a similar result. Nothing in this study provides a clear picture of what those environmental factors are but a simple environmental explanation (e.g., poor parenting) or genetic source (single gene, or uniform action of several genes) is not supported here.

Rahman added in the Post article:

“Overall, genetics accounted for around 35 percent of the differences between men in homosexual behavior and other individual-specific environmental factors (that is, not societal attitudes, family or parenting which are shared be twins) accounted for around 64 percent. In other words, men become gay or straight because of different developmental pathways, not just one pathway,” Rahman said.

Filed under: Research news, sexual orientation by Warren - 27 Comments →

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.

Filed under: Research news, sexual orientation by Warren - 239 Comments →

A new study released online with Archives of Sexual Behavior and via press release today propose a relatively small role for family attitudes in the direction of sexual attraction, with more of the explanation being factors not shared by siblings.

Society’s attitudes have little impact on choice of sexual partner

[PRESS RELEASE 16 June 2008] A unique new study from the Swedish medical university Karolinska Institute (KI) suggests that the attitude of families and the public have little impact on if adults decide to have sex with persons of the same or the opposite sex. Instead, hereditary factors and the individual’s unique experiences have the strongest influence on our choice of sexual partners.

The study is the largest in the world so far and was performed in collaboration with the Queen Mary University of London. More than 7,600 Swedish twins (men and women) aged 20-47 years responded to a 2005 - 2006 survey of health, behaviour, and sexuality. Seven percent of the twins had ever had a same-sex sexual partner.

“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.”

The conclusions apply equally well to why people only have sex with persons of the opposite sex as to why we have sex with same-sex partners. However, the conclusions are more difficult to transfer to countries where non-heterosexual behaviour remains prohibited.

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.

Publication:
Niklas Långström, Qazi Rahman, Eva Carlström, Paul Lichtenstein, “Genetic and Environmental Effects on Same-sex Sexual Behaviour: A Population Study of Twins in Sweden.” Archives of Sexual Behaviour, 7 June 2008, doi 10.1007/s10508-008-9386-1

This is more evidence that different factors operate differently for different people. In discussing sexual orientation, it may be that individual narratives have validity for the individual but cannot be generalized widely. Where have I heard that before?

Another news item is circulating today with what appears to be a mix of new and old research on brain structure and sexual orientation.

UPDATE - There is indeed new research from Ivanka Savic’s team in the Proceedings of the National Academies of Science. The study, titled “PET and MRI show differences in cerebral asymmetry
and functional connectivity between homo- and heterosexual subjects” by Ivanka Savic and Per Lindstrom is not yet published but I have a copy and am reviewing it.

Filed under: Professional issues, Research news, sexual orientation by Warren - 55 Comments →

The Irish Iris Robinson controversy appears to have quieted down somewhat. I noted last week that Northern Ireland’s “first lady” entered controversial waters by declaring homosexuality an abomination, with subsequent embellishments. Mrs. Robinson further recommended therapy for gays to change via a psychiatrist, Paul Miller, who advises Mrs. Robinson on health matters.

As noted in my initial post on this topic, I wrote to Paul Miller to ask him if he endorsed the bioenergetics techniques of Richard Cohen. This was a relevant question since Dr. Miller organized a training led by Mr. Cohen in November, 2007. Dr. Miller did not directly answer that question but instead referred me to the website of his organization - Abeo. What is Abeo?

ABEO is an umbrella organization, set up by Dr Paul Miller, of like-minded mental health professionals who want people to be all that they can be; so that they may experience deeper joy in their lives. Our tag-line, ‘joy through change’ captures the heart of this vision.

What does ABEO mean?
ABEO in Latin means, ‘to pass away’ or ‘to come to an end’, but in Nigerian it means ‘my arrival brings joy’. By taking this name we want to show that our mission is to show that all of us experience pain of different sorts, however, when faced with issues that bring pain into our lives we can be empowered to overcome them and experience joy through finding healthy adaptations to meet our core needs.

There is much emphasis on this site about meeting core needs, especially masculinity. There are pages on manhood and gender identity which look familiar to anyone conversant in reparative drive perspectives on same-sex attraction. On the Gender Identity page, links are provided to Jonah, NARTH, Mankind Project, New Warriors Training Adventure, Internation Healing Foundation (Richard Cohen), and People Can Change.

The approach to therapy is called “gender affirming therapy” and is designed to address same-sex attraction through enhanced masculinity. Abeo says:

Where a person experiences unwanted SSA we can provide expertise and therapy to help the person meet their core unmet needs in a way that allows them to resolve their SSA and so move towards a fuller expression of masculinity and a heterosexual expression of that gender identity.

Abeo also offers training to mental health professionals, which presumably included the Cohen visit to Northern Ireland. About the training, Abeo says:

ABEO also provides training to those professionals working in the area of unwanted SSA. Through links with NARTH, JONAH, the International Healing Foundation and a number of international experts we are seeking to spread evidence based skills that will help professionals working in this area.

Given the aspiration of teaching “evidence based skills,” the links provided are puzzling. Where is the evidence that the kinds of masculinity-building interventions promoted by these organizations “resolve” SSA toward a “heterosexual expression?” As we have noted, MKP in the US has been through all of that with many manly gay warriors happy to dispute these claims.

Another aspect of this story that is interesting to me is that I expected this site to be more Christian-based given Iris Robinson’s strong words of a referral. MKP and NWTA certainly do not point their participants to Christianity as a means of manly identity. The UK Scouting Association issued an advisory warning scouting groups not to rent camps to the MKP. In the US, the ex-gay organizations can be divided into those who seem to be faith-based and those that are based in the men’s movement. If that division is real in the UK, it seems clear from a review of Abeo that the men’s movement ex-gay wing got a major plug from the first lady.

Filed under: IHF, Journey into Manhood, NARTH, New Warriors Training Adventure, Professional issues, Religion and sexuality, Richard Cohen, ex-gay, sexual identity, sexual orientation by Warren - 1 Comment →

Iris Robinson, the “first lady” of Ireland and also a MP (member of Parliament) from Northern Ireland has stepped into controversy with comments about her oppostion to homosexuality and her beliefs that gays can change with counseling. With what should seem in hindsight to be a very poor sense of timing, she made her negative comments about homosexuality in response to a question about a hate crime in Belfast, Northern Ireland directed toward a gay man. Taking a page from the Sally Kern playbook, she expressed no regrets for her comments which were more harsh than a simple recitation of her moral opposition (see this article…).

About reorientation therapy, Mrs. Robinson said:

‘I have a lovely psychiatrist who works with me and his Christian background is that he tries to help homosexuals - trying to turn them away from what they are engaged in…”

Subsequently, the psychiatrist involved, Paul Miller, gave an interview to a Belfast newspaper and appeared on radio to address the claims of change therapy. Paul Miller is a psychiatrist who is a senior advisor to Mrs. Robinson and works extensively with post-traumatic stress. He is also a former trainee of Richard Cohen. Cohen presented a workshop in Northern Ireland in November of 2007 with Paul Miller as the contact person.

In an email to me, Dr. Miller said Cohen’s training was “a very valuable part of their attempt to equip themselves for working in this area.” It must have been well received since three points cited by Dr. Miller are taken in the same order from Richard Cohen’s website.

Dr Miller said three key messages summed up his work.

“First, no one is born gay because gay identity is a complex interaction between genetics and environment; second, no one chooses to experience who they are sexually attracted to; and thirdly, change in sexual orientation is possible.”

Compare those points with the front page of the International Healing Foundation.

I have not received a reply to my questions about whether the bioenergetic and holding therapy approaches were demonstrated or make up a part of Dr. Miller’s work.

Meanwhile, Mrs. Robinson is being investigated for violating laws relating to hate speech. Unfortunately, some Christian conservatives will turn this event into a debate over free speech. As with Sally Kern, Mrs. Robinson may have the right to say what she did (actually in Ireland, she may not; we shall see…), but having the right doesn’t make it right. In response to questions about homosexuality, and in the context of discussion over a hate crime, why not simply express opposition to violence and hatred? Actually, in any context or at any time, I do not think it furthers any good purpose to engage in such ungracious and uncivil rhetoric.

Her pairing of comments about change therapy and the hate crime, along with her negative comments about homosexuality make it very clear to me that Christian sexual identity ministries should make their opposition to violence and harassment very clear.

Here is another Sally Kern moment; what will happen in it?

Filed under: Media and society, Religion, Religion and sexuality, antibullying, sexual orientation by Warren - 15 Comments →

I am not a very consistent blogroller. Up to now, my list of links has been an after thought. I am not sure I will stay on top of things but I have added some new ones.

I want to mention four of the new links. First, go visit John Shore’s blog - Suddenly Christian. John is a winsome, funny, prolific and lately, controversial Evangelical writer who produces some entertaining and thoughtful posts. John is an adult convert to Christianity who brings a fresh and sometimes uncomfortable perspective to the Evangelical world.

The Marin Foundation is the brainchild of Andrew Marin. Not a blogger - yet - Marin seeks to do research and build bridges between religious and LGBT communities with an ambitious mission and set of values. He may in the middle enough to bother some people on either extreme, but this is where he believes he should be. He is currently writing a book about his views.

Wayne Jacobsen is on a roll. He published the NY Times #1 best seller, The Shack recently and it has changed his life. His blog is a bridgebuilding effort, which is a natural outgrowth of his work with Bridgebuilders. Wayne was a catalyst behind the First Amendment Center Guidelines on Sexual Orientation in schools. I have been a friendly acquaintance of Wayne via a meeting at Grove City College through mutual friends about three years ago.

It has taken me too long to put up a link to Mark Yarhouse’s Institute for the Study of Sexual Identity. The front page reads like a blog although without comments. Mark work on narrative sexual identity therapy was featured in a recent American Journal of Family Therapy article and is referenced at the ISSI site.

Enjoy!

Filed under: Blogkeeping, sexual identity, sexual identity therapy, sexual orientation by Warren - 7 Comments →

As a follow up to the recent broadcasts by NPR and several posts regarding gender identity, here is a Q & A involving J. Michael Bailey and Ken Zucker recently posted on the SEXNET email list. Dr. Zucker is the Head of the Gender Identity Service, Child, Youth, and Family Program and Psychologist-in-Chief at the Centre for Addiction and Mental Health in Toronto, Ontario, Canada. Dr. Zucker is the chair of the newly appointed Sexual and Gender Identity Disorders working group for the 5th edition of American Psychiatric Association’s Diagnostic and Statistical Manual (DSM-V). Dr. Bailey is Professor of Psychology at Northwestern University, prolific sexual orientation researcher and moderator of the SEXNET list. As the NPR article noted, Dr. Zucker has extensive clinical and research experience with persons who experience gender dysphoria. This interview was conducted by Dr. Michael Bailey via email and has been slightly edited for posting here. Both Drs. Bailey and Zucker have reviewed and approved it.

Bailey: Both NPR shows used the phrase “a girl trapped in men’s bodies.” How common is this concern over body image?

Zucker: I would say that, in general, there has not been a lot of good empirical research on body image issues in pre-pubertal children with GID. In adolescence, the Dutch group has reported clear evidence of body image dissatisfaction as one finds in adults. One of my PhD students has a dissertation that should be defended later this year in which we studied body image in boys with GID compared to clinical and community controls. We did detect significant body image differences among the three groups: body image in general and in relation to gender-specific anatomic dysphoria. The boys with GID had a poorer body image in general and, of course, with regard to gender-specific anatomic dysphoria. It is only a first pass at this issue and I will report on this down the road after the dissertation is defended.

Bailey: The case on the second NPR show is of a child (natal boy) who had extreme temper tantrums when not allowed to engage in feminine behaviors. Is this common in the kids you see, or is there something unusual about these kids?

Zucker: This is not uncommon. Some parents will report that if they try to limit cross-dressing that this can be very distressing for the boys. Some parents describe it as “he needs his fix.”

Bailey: You are more familiar than anyone else I know with the difference between the British and Dutch treatment centers that yielded the findings that only 20% of the British kids but 100% of the Dutch kids pursued sex reassignment eventually. Did the Dutch center focus on older children (who were less likely to change their minds)? To the extent that the samples were comparable, it is a shocking difference in outcome.

Zucker: I don’t think the British group has published their data yet. But, yes, the Dutch group data are on adolescents and I think that the British group is talking about clients first seen in childhood, not adolescents. The Dutch group now has a paper that is close to being “in press” on their first follow-up of GID children and then followed up later. The GID persistence rate for their boys was about 20% and the persistence rate for girls was 50%. Their persistence rate for boys appears to be similar to what I have summarized for the boys seen in my clinic (Zucker, 2005), but higher than the 12% rate for girls that we published earlier this year (Drummond et al., 2008). The Dutch group speculates that their girls were, at initial presentation, more extreme in their cross-gender behavior than the girls that we reported on, but that will require more careful analysis.

Bailey: The NPR show, and some people on it, kept implying that some of these kids are “really” transgender, and others are not. I suspect you don’t agree with this way of thinking about it, although you recognize that some kids are more likely to become transgender adolescents and adults than other kids are. Can you remind us which factors are associated with persistence of GID from childhood?

Zucker: I don’t think we know yet. Two possible candidates are age at initial evaluation (later age associated with greater persistence rates) and quantitative metrics of cross-gender behavior in childhood.

By persistence rate, Dr. Zucker is referring to the percentage of GID children who are still GID at a later assessment. In the Dutch group, as well as in Dr. Zucker’s research sample, most boys who want to be girls in childhood, end up as men who do not want to be women. For women in the Dutch sample, half remain GID. I think the assessments of low persistence of GID provide some helpful information to parents who wonder about puberty delay and behavioral interventions with their GID children.

Thanks to Drs. Bailey and Zucker for permission to post this conversation.

Filed under: Professional issues, Research news, gender identity, sexual orientation by Warren - No Comments →