Tag Archives: Germany

Orgasm after Vaginoplasty

Orgasm and sexual pleasure are important goals of gender reassignment surgery (GRS). Most trans women report being able to orgasm after penile-inversion vaginoplasty with clitoroplasty using the glans penis.* However, some are not able to orgasm and some report difficulty orgasming.

Two large studies found that 18% of trans women were not able to orgasm by masturbation after surgery. In one of the studies an additional 30% of the women had difficulty orgasming from masturbation.

The number of women who couldn’t orgasm went down to 14% or 15% when they included all sexual activities.

Other recent studies** have found numbers of anorgasmic women ranging from 0% to 52%, although most results were close to 18%.

It is clear that a significant percentage of trans women are not able to orgasm after this type of vaginoplasty, but it is not clear exactly how many.

SOME RECENT STUDIES OF ORGASM AFTER GRS

There were five studies where the women had clearly been sexually active:

Lawrence, 2005 – anonymous questionnaires from 232 trans women, 227 answered the question on orgasm by masturbation:

18% were never able to achieve orgasm by masturbation.

15% were rarely able to orgasm with masturbation.

15% were able to orgasm less than half the time by masturbation.

However, it seems that only 15% were completely unable to orgasm. “About 85% of participants who responded to questions about orgasm were orgasmic in some manner after SRS [GRS].” 

Imbimbo et al., 2009 – 139 trans women (93 questionnaires at clinic, 46 phone interviews):

14% of the trans women complained of anorgasmia

18% of the trans women were never able to orgasm by masturbation (out of 33 women who masturbated)

33% of the trans women were never able to orgasm by vaginal intercourse and 25% seldom orgasmed this way (out of 60 women having vaginal intercourse)

22% of the trans women were never able to orgasm by anal sex and 13% seldom did (out of 75 women having anal sex)

56 women had oral sex, but the study gives no numbers for orgasm.

Buncamper et al., 2015 – 49 trans women completed questionnaires:

10% had not had orgasm after surgery, although they had tried.

Selvaggi et al., 2007 – 30 trans women were personally interviewed by a team of experts:***

15% had not experienced orgasm after surgery during any sexual practice.

Giraldo et al., 2004  – 16 trans women were given structured interviews at follow-up visits:

0% had problems – all the women reported the ability to achieve orgasm

Note: This study is about a modification to the technique for creating a clitoris.

There is one study where 18% of the women never orgasmed after surgery, but it is not clear if they were sexually active or not:

Hess et al., 2014 – 119 trans women completed anonymous questionnaires, 91 answered the question “How easy it is for you to achieve orgasm?”:

18% said they never achieve orgasm

19% said it was rarely easy for them to achieve orgasm

The other studies above asked about sexual activity or gave the women an option to say the question did not apply or they had not tried. This one did not.

On the other hand, some people did not answer the question, so perhaps women who were not sexually active skipped the question on orgasm.

There are three studies that only give brief information on how many women could orgasm; it is not clear what is going on with the rest of the women.

Perovic et al., 2000 – 89 trans women were interviewed:

It looks like 18% had not experienced orgasm during vaginal sex, but it is possible that some of the women were not sexually active.

“Information on sensitivity and orgasm was obtained by interviewing the patients; the sensitivity was reportedly good in 83, while 73 patients had experienced orgasm.”

and

“If the penile skin is insufficient, the creation of the vagina depends on the urethral flap, which also provides moisture and sensitivity to the neovagina. The results of the interviews showed that orgasm was mainly dependent on the urethral flap.”

Goddard et al., 2007 – 70 trans women were interviewed by a telephone questionnaire; 64 of them had had a clitoroplasty:

It looks like 52% of the women with clitorises were not able to achieve clitoral orgasm, but again it is not clear if they were sexually active.

“Clitoral sensation was reported by 64 patients who had a neoclitoris formed and 31 (48%) were able to achieve clitoral orgasm.”

14% of the women complained of “uncomfortable clitoral sensation.”****

Wagner et al. (2010), – 50 trans women completed a questionnaire:

It looks like between 17% and 30% were not able to achieve clitoral orgasm.

“Of the 50 patients, 35 (70%) reported achieving clitoral orgasm” but

“90% of the patients were satisfied with the esthetic results and 84% reported having regular sexual intercourse, of whom 35 had clitoral orgasm.” 

If we look only at the group having regular intercourse, 17% of them are not having clitoral orgasms. But were the women not having intercourse masturbating and unable to orgasm? If so, they were also sexually active and the 30% number is the relevant one.

The study gives very little information on the questionnaire and results, but it seems surprising that 83% of the women were having clitoral orgasms from sexual intercourse; that is not typical in cis women.

A final study asked about pleasurable sexual intercourse, not orgasm:

Salvador et al., 2012 – 52 trans women participated in the study. It is unclear how they were surveyed, but based on this earlier study, it could have been a combination of a questionnaire and interview.

8% did not consider vaginal sex pleasurable.

However, only one woman said sexual intercourse was unsatisfactory (2%) while 10% of the women said it was average; presumably some of the women who said it was average also said it was pleasurable and some did not.

About Orgasms

Freud believed that women had vaginal and clitoral orgasms; unfortunately he also believed that vaginal orgasms were superior and mature women should give up clitoral orgasms. In the 1960s Masters and Johnson showed the physiological basis for clitoral orgasms in the lab; they argued that orgasms during intercourse were also clitoral orgasms, just harder to achieve. More recently, some sexologists have shown that some women have G-spot orgasms during intercourse, although not all experts believe in them.

For most women it is easiest to have an orgasm from masturbation or clitoral stimulation. Most women are not able to have clitoral orgasms during vaginal intercourse without additional clitoral stimulation. Some women experience other types of orgasms during vaginal intercourse.

Although trans women’s biology is somewhat different from cis women’s, their clitorises are formed from the most sensitive area of the penis. Therefore, we might expect trans women to have orgasms most easily from masturbation of the clitoris; the study by Imbimbo et al. that compares different sexual activities supports this hypothesis.

It also makes sense that when we look at orgasms from all sexual activities, we find more trans women are able to orgasm than when we look at just clitoral orgasms; some trans women may be having G-spot orgasms involving their prostate gland.

Interestingly, Imbimbo et al. found that it was easier for trans women to have orgasms from anal sex than vaginal sex (65% of the women often had orgasm from anal sex, 35% seldom or never did; 42% of the women always or often had orgasm from vaginal sex and 58% seldom or never did). Furthermore, more of the trans women were having anal sex than vaginal sex (54% versus 43%). Perhaps they had more experience with anal sex before surgery or perhaps anal sex worked better for some women.

Studies that simply ask about orgasm without talking about what type of orgasm or sexual activity is involved do not give enough information about what is happening. Future studies that include this information would make it easier to compare the results and to improve outcomes.

Comparing the Studies

It is difficult to compare the results of the studies. The studies are of surgery at different clinics around the world; the work is being done by different surgeons and may involve variations in technique. Some of the surgeries are more recent than others as well.

In addition, the studies use different methodologies to collect data and they do not ask the same questions. Some are focused on clitoral orgasms, others talk about orgasm during intercourse, some studies talk about masturbation, and some are vague about what they mean by orgasm.

As is common in follow-up studies, almost all of the studies had a significant drop-out rate; not everyone who had the surgery participated in the study. This could create a bias in either direction – people who regret the surgery might be too depressed to respond to the clinic or people who were dissatisfied might be more motivated to participate in the study.

The method of the study could also introduce biases; people may be more likely to tell the truth in an anonymous survey than in an interview. On the other hand, interviews may allow for follow-up questions and clarifications.

With only 10 studies that are so different it is impossible to come to any definitive conclusions about orgasm after GRS. I like to believe that Goddard et al.’s numbers of anorgasmic women are so high because some of them were sexually inactive or because their study included women 9-96 months after surgery. It could also be something to do with their surgical technique. After all Perovic’s et al.’s study also included women 0.25-6 years after surgery and some of them may have been sexually inactive, but their numbers were much better.

I suspect that the reason all of Giraldo et al.’s patients were orgasmic is that their sample size is so small, but again, it could be that they have a superior technique.

It might be that Buncamper et al. had better numbers than most of the studies because their patients had surgery more recently with improved techniques, but it might also be because their study was smaller.

With so few studies, I could find no clear pattern based on when people had surgery, how data was collected, or follow-up time after surgery. For further information on the studies, see this appendix.

What is clear is that we need more research on patients who are not able to orgasm after surgery. Are some people more at risk than others? Does the surgical technique make a difference? What role does aftercare play?

Is being non-orgasmic just a possible complication of the surgery? If so, how common is it?

And most important, what can be done to enable all trans women to be able to orgasm after surgery?

 

 

 

*I did not find data on orgasm after intestinal vaginoplasty. According to this 2014 review of studies, most studies of intestinal vaginoplasty did not look at sexual function; for those that did the review reports a score for sexuality rather than information on orgasms.

** I have excluded studies published before 1994 and studies where all of the surgeries were performed before 1994. The studies by Imbimbo et al. and Selvaggi et al. may include some participants who had surgery before 1994.

*** The exact number of the participants is unclear because this study is one of a pair using the same participants. The other study by de Cuypere et al. did in-depth interviews with 32 trans women while this one focused on testing the sensitivity of the genitals for 30 trans women. Unfortunately, the de Cuypere study reports data in terms of how many women “Never-sometimes” had orgasm so their data is not comparable to other studies. (They found that 34% of the women never-sometimes had orgasm during masturbation and 50% never-sometimes had orgasm during sexual intercourse.)

**** Goddard also reports that despite problems, “no patient elected to have their clitoris removed.” Is the man mad?

Male-to-Female Transsexualism: Technique, Results and 3-Year Follow-Up in 50 Patients – Study Review

This is a 2010 study of the functional and cosmetic outcomes of the surgical techniques used at a German clinic. They followed 50 trans women who had surgery between May 2001 and April 2008. The surgeries were all performed by the same surgeon who had extensive surgical experience.

Before surgery, all the patients had completed a two year “real life” test and had been recommended for surgery by two independent psychiatrists. They had been on hormones for at least one year, although they stopped taking hormones a month before the surgery.

The patients were sent a questionnaire to follow-up on sexual function and patient satisfaction with the surgery. All 50 patients completed the questionnaire; the mean follow-up time was 3 years.

Outcomes of Surgery

Regrets:

One person regretted the surgery and became clinically depressed. They attempted suicide twice and had not fully recovered two years later.

The patient was 24 years old and the authors suggest that the ideal age for surgery is 30 years old. They also recommend thorough evaluation and good counseling before surgery.

This is consistent with other studies that found a regret rate after surgery of 3-4%. In a group of 50 people getting the surgery, you would expect one or two people to wish that they had not had the surgery.

The patient regretted the surgery 3 days after the operation.

Complications:

6% had bleeding after surgery

4% required operative revision due to the bleeding (two of the three who had bleeding)

10% had shrinkage of the vagina which could be corrected by a second surgical intervention

4% had a minor bulge in the anterior vaginal wall which could be easily fixed with simple excision

There were no post-operative rectocele (bulge of the rectum into the vagina) or urethrovesical fistulae.

The authors of the study say that the incidence of surgical complications was comparable to the data in the literature.

The 6% of patients with bleeding that they report is better than the 10% reported by a United Kingdom clinic in this review.

Their rate of complications is considerably better than this 2001 study at a different German hospital which reported that “Major complications during, immediately and some time after surgery occurred in nine of the 66 patients (14%), including severe wound infections in six, a rectal lesion in three, necrosis of the glans in three and necrosis of the distal urethra in one. Minor complications, e.g. meatal stenosis in seven patients, occurred in 24 (36%) of patients.”

They do not report any problems with narrowing of the urethra, which is also an improvement over the 3-4% reported by the clinic in the Untied Kingdom.

They do not report any problems with pulmonary embolisms or fistualae between the rectum and vagina. These are problems that are relatively rare and you might not expect to see them in a group of only 50 people; the review from the United Kingdom reported a rate of 2 in 1000 pulmonary embolisms with 1 death. They also reported a rate of 6 in 800 rectal fistulae.

Minor complications:

6% subcuntaneous hematoma that did not require any further therapy (i.e. they had a ruptured blood vessel causing a lump or bruise under the skin)

General:

Mean operative time – 190 (160–220) minutes or 3.16 (2,66- 3.66) hours

Mean depth of the vagina – 10 (6–14) cm or 3.93 (2.36-5.51) inches

Median hospital stay – 10 (6–14) days

In comparison, the United Kingdom clinic reported an operative time of 120-150 minutes, while the 2001 German study reported a mean time of 6.3 hours with a range of 4-9 hours.

Satisfaction with results at follow-up

Appearance:

10% of the patients were dissatisfied with the appearance of their labia

90% were satisfied with the appearance of their genitals

We need more research on how to construct labia that are satisfactory for all trans women.

Depth of Vagina:

20% were dissatisfied with the depth of their vagina

80% were satisfied with the depth of their vagina

4% were still dissatisfied with their vagina after a second operation

Of the ten women who were dissatisfied with the depth of their vagina, eight had a new operation to augment the vagina. Of the women who had the second operation, two were still dissatisfied (25%). Perhaps the secondary operation could be improved.

We need to know more – why were 20% dissatisfied with the depth of their vagina? What can be done to ensure that all trans women have vaginas that are deep enough?

How deep were the vaginas at follow-up? Were there some women whose vaginas were not deep who were satisfied anyway?

Sexual Pleasure:

5% of the trans women having regular sexual intercourse experienced pain during intercourse; 84% of the trans women were having regular sexual intercourse

70% of the trans women reported achieving clitoral orgasm

The authors are not clear here, but it looks like 30% of the trans women who had this surgery are unable to achieve orgasm. This is a serious problem; they should have addressed it more fully.

Were some of the women not attempting orgasm? Did everyone answer the question?

At one point the authors say, “84% reported having regular sexual intercourse, of whom 35 had clitoral orgasm” – that would change the numbers to 35 out of 42 women which would be better (although it would still leave 17% of the sexually active women not having orgasms). On the other hand, they also say, “Of the 50 patients, 35 (70%) reported achieving clitoral orgasm.”

As it stands, it looks like a large percentage of trans women are not having orgasms after surgery. That would be a problem and worthy of more discussion in the results. The ability to orgasm is an important, vital aspect of the outcome of these surgeries.

In addition, doctors and surgeons need to address the problem of pain during intercourse. Is there something trans women can do themselves to reduce the pain? Can the surgeries be improved in this area?

From their Discussion and Conclusions:

“The incidence of surgical complications was comparable to the literature data. The most common complication (10%) in the follow-up was shrinkage of the neovagina. In all cases a second surgical correction was necessary to definitively solve the problem. In all patients vaginopexy to the sacrospinous ligament was carried out, reducing the rate of neovaginal prolapse as described in the literature.

After 3 years, 49 patients were satisfied and did not regret or had doubts about having undergone sexual reassignment surgery. The only exception was a 24-year old patient who, 3 days after the operation, regretted his decision. After that, he developed a strong depression which needed psychological therapy. Two years after surgery, the patient had still not recovered completely and had attempted suicide twice.

We agree with Rehman and Melman that the best age to undergo sexual reassignment surgery is 30 years, an age that enables patients to adjust socially and sexually, increasing the possibility to develop attractiveness and allowing the patients to mature in dealing with new life stresses. Moreover, before undergoing such surgery, it is our opinion that all patients at all ages need deep and intensive psychological examination and must be informed about all the functional and cosmetic risks associated with this operation and, above all, about the impossibility of regretting the decision and returning to their natural gender.

With improvements in surgical technique over the years, male-to-female gender-transforming surgery can assure satisfying cosmetic and functional results, with a reduced intra- and postoperative morbidity. Nevertheless the experience of the surgeon and the center remains a central important aspect for obtaining optimal results.”

The full article includes graphic pictures of surgery as well as details of their technique; you can get it at the link below.

Original Source:

Male-to-Female Transsexualism: Technique, Results and 3-Year Follow-Up in 50 Patients by Wagner S, Greco F, Hoda MR, Inferrera A, Lupo A, Hamza A, Fornara P in Urol Int. 2010;84(3):330-3.

Word of the Day

Geschlechtsumwandlungstreib – the drive for sex transformation.

This word was invented by Max Marcuse in 1913.

From Transgender History by Susan Stryker.

 

You can buy Transgender History:

from Seal Press (support women’s publishing)

from Barnes and Noble (support brick and mortar stores)

from Amazon (support books)

Gender dysphoria in adolescents: difficulties in treatment – Extremely Brief Review

This is a review of an abstract; the original article is in German and I don’t have access to it.

“In many children and adolescents with gender dysphoria only minor or no psychopathology is found.”

However, 43% of the patients seen at the Frankfort University Gender Identity Clinic for children and adolescences have serious mental health issues.

This creates problems in treatment.

The article then discusses four sample cases to show some of the difficulties.

In two cases, “major psychopathology made decision for reassignment very difficult.”

In two other cases, the patients were “not able to follow recommended treatment steps, in these patients diagnostic doubts arose.”

it’s impossible to know what this means without knowing more about the study and about other gender identity clinics.

Clearly, however, there is a need for more research. Why did this gender clinic see so many children and teens with serious psychopathology? What about other gender clinics? How does this compare to the past? How many patients are we talking about? What were the mental health issues? Did any of the patients have autism spectrum disorders?

Original Source:

“Gender dysphoria in adolescents: difficulties in treatment” by Meyenburg B in Prax Kinderpsychol Kinderpsychiatr. 2014;63(6):510-22.

Characteristics of children and adolescents with gender dysphoria referred to the Hamburg Gender Identity Clinic – Brief Review

This article is in German, so I have only seen the abstract.

Demographic data on trans kids and teens is generally lacking, but there seems to be an increase in diagnoses of gender dysphoria.

“Given the increasing demand for counselling in gender dysphoria in childhood in Germany, there is a definite need for empirical data on characteristics and developmental trajectories of this clinical group.”

This study looked at the patients at one clinic and found that there were significant differences between the girls and boys with gender dysphoria. They suggest that the two groups will need “different awareness and individual treatment approaches.”

Between 2006 and 2010, the Hamburg Gender Identity Clinic saw 45 “gender variant” children and teens. 40 of these patients were diagnosed with gender identity disorder (88.9%).

Differences reported between girls and boys with gender dysphoria:

The girls were older than the boys on average.

A higher percentage of the girls were referred to the clinic at the beginning of adolescence (over 12 years old), although more girls reported an early onset of gender dysphoria.

More of the girls talked about their “(same-sex) sexual orientation during adolescence and wishes for gender confirming medical interventions.”

More of the girls reported self-mutilation in the past or present.

More of the girls reported suicidal thoughts and/or attempts.

The referral rate of girls with gender identity disorder was higher than the rate for boys. They give the ratio 1:1.5. (I am not sure what this means; this is a translation of an abstract.)

Original Source:

“Characteristics of children and adolescents with gender dysphoria referred to the Hamburg Gender Identity Clinic” by Becker I, Gjergji-Lama V, Romer G, Möller B. in Prax Kinderpsychol Kinderpsychiatr. 2014;63(6):486-509.

Transgender History by Susan Stryker – book recommendation

This is a great book. Read it.

Don’t you wish you could have turned in a book report like that? Sweet and simple.

This blog is about science, but I’ve decided to throw in some occasional book recommendations. I’ll be quoting Stryker’s history from time to time as well.

Meanwhile, other people have already written thorough reviews: C. Riley Snorton at the University of Pennsylvania, A Gender Variance Who’s Who, or plain old GoodReads.

You can buy Transgender History by Susan Stryker:

from Seal Press (support women’s publishing)

from Barnes and Noble (support brick and mortar stores)

from Amazon (support books)

A review of “Gender Identity Disorder in Twins: A Review of the Case Report Literature”

The data on twins suggests that there is a genetic component to gender dysphoria.

It also suggests that other factors are involved in developing gender dysphoria.

Unfortunately, the data is weak because it is mostly made up of case studies.

In addition, the data on identical twins and the data on fraternal twins were collected in different ways.

It is possible that this review overestimates the influence of genes due to the way the data was collected.

I had thought that writing this review would be quick and easy; genes are involved, but they are not the only factor. The truth is that the data is flawed and we don’t have conclusive proof yet. What we do have is a suggestion that genes are involved in gender dysphoria and a need for more research in this area.

Data on twins with gender dysphoria is hard to collect because it is rare. This review is an important one and it shows that there are good reasons to keep looking for possible genetic links to gender dysphoria. It also shows that there are good reasons to look for non-genetic factors that play a role in developing gender dysphoria.

Now you have the summary of the results, back to the study. Why does it mattter if many of the reports on identical twins came from case studies?

Using case studies means that there is a possibility of selection bias.

People may be more likely to publish interesting cases. For example, the review includes one case study where both identical twins had gender dysphoria, but only one had schizophrenia. In another case study both identical twins had anorexia, but only one had gender dysphoria. These cases are interesting, but they may not be typical.

This can become a more serious problem if therapists are more likely to be interested in cases of twins who are both trans. Alternatively, there could be a selection bias in favor of writing about identical twins where only one twin is trans. Some therapists might unconsciously look for cases of twins that fit their own theory about the cause of gender dysphoria. (Read more about case studies and selection bias here.)

The results of this review suggest that there is a selection bias that favors identical twins over fraternal twins. In other words, people write up and publish cases of identical twins more often than fraternal twins.

This is not because trans people don’t have fraternal twins; the studies that reviewed clinic records found 19 sets of fraternal same-sex twins and only 7 sets of identical twins. Only 27% of the twins in this group were identical twins. This is not surprising; fraternal twins are more common than identical twins in the general public.

The other studies, in contrast, reported on 16 sets of identical twins and only 2 sets of fraternal twins. A whopping 89% of the twins in this group were identical twins.

The key to figuring out if gender dysphoria is genetic is to compare identical twins and fraternal twins. If identical twins are more likely to both have gender dysphoria than fraternal twins, you have a good case for a genetic contribution. So if the sets of identical twins are chosen in a different way from the sets of fraternal twins, you have a problem.

In fact, for this study most of the data on identical twins is coming from case reports; there might be a selection bias involved there. Almost all of the data on fraternal twins, however, is coming from comprehensive reviews of clinic records.

Reviews of case studies include a number of other problems.

You can’t be sure people are being diagnosed in the same way; you may not be looking at the same phenomenon. This review looked at people diagnosed by different therapists in at least ten different countries.* The dates of the studies ranged from 1956 to 2011. Some of the twins were children or teens, some were adults.

There may also be cultural or environmental differences that are relevant. For example, one of the case studies is of a pair of identical twins in Iran. Both twins are trans. We know that many people feel pressured to transition in Iran; what if that is a factor in this particular case? What if in another country, only one of the twins would have transitioned?

The era of the study might also affect gender dysphoria. For example, the Belgian clinic noticed that two of the fraternal twins with gender dysphoria they found had been born after in vitro fertilization. If IVF is a factor in gender dysphoria, it will only affect later cases.**

The data in case studies is not uniform; this makes it hard to compare. For example, one study discussed birth weights while another focused on relationships with parents.

This review of studies did include three sets of twins who were found in a method that did not have a selection bias or problems with inconsistent collection of data.

1) Zucker looked at the records of 561 patients who went to a Canadian clinic for gender dysphoria between 1976 and 2011 and found 25 sets of twins. The patients were all under 12 years old.

They found no cases where both twins had gender dysphoria.

2) Heylens and De Cuypere looked at 3 sets of adult twins from the 450 patients who went to a Belgian gender clinic between 1985-2011 plus 3 sets of non-adult twins who went to the Belgian gender clinic for children and teenagers.

They found only one case where both of the twins had gender dysphoria: a set of identical twins who were female-to-male transgender (FtM).

3) Vujovic et al reviewed all the cases of gender dysphoria who were treated at a Serbian clinic between 1987 and 2006. Out of 147 people, one trans man and one trans woman had a fraternal twin. Neither of their twins had gender dysphoria.

If we exclude case studies because of possible bias, we end up with no genetic component to gender dysphoria in trans women. None of the clinics found pairs of male twins who both had gender dysphoria.

The problem with this approach is that identical twins who are both male-to-female transsexuals exist. They just didn’t show up at these three clinics. Presumably, they are very rare.

Using the clinic studies for trans men we would have one set of identical Belgian twins who both had gender dysphoria, and one set of identical Canadian twins who did not. In addition, we would have three sets of fraternal twins where only one twin had gender dysphoria. This is not enough data.

So it makes sense to look at the data from individual case studies; we just need to be cautious about interpreting it. It is possible that it would over or underestimate the genetic component to gender dysphoria.

What was the data, then?

The authors searched the literature and put their data from the three clinics together with data from 17 different case reports and studies.***

They found:

FtMs with identical twins

3 sets of identical twins who both had gender dysphoria (37.5%)

5 sets of identical twins where only one of the twins had gender dysphoria (62.5%)

FtMs with fraternal twins

5 sets of fraternal twins where only one of the twins had gender dysphoria (100%)

MtFs with identical twins

6 sets of identical twins where both twins had gender dysphoria (40%)

9 sets of identical twins where only one twin had gender dysphoria (60%)

MtFs with fraternal twins

16 sets of fraternal twins where only one twin had gender dysphoria (100%)

Based on this data, identical twins with gender dysphoria are more likely than fraternal twins or the general public to have a twin with gender dysphoria. This suggests a genetic component to gender dysphoria.

However, most of the time, only one identical twin has gender dysphoria. This suggests other factors are involved in gender dysphoria.

At this point, we have no idea what the other factors involved might be. The case reports don’t give enough information on the twins to figure it out. The information they give is inconsistent; one study reported on the age of the first period while another talked about whether or not the mother was domineering. In addition, we may be comparing apples and oranges; for example, one study looked at an adult male American Indian in 1976, another looked at 13 year old American females in 1992.

The authors of the review conclude:

“The etiology of GID is a complex process of biopsychosocial components with unexplained interactions. Twin literature on GID supports the contribution of genetic factors to the development of gender identity with a higher tendency in males than in females.****

Since sample size is still limited and genotype studies are lacking, conclusions must be drawn with caution.

Therefore, detailed registers of GID twins, preferably on MZ twins discordant for GID and DZ twins are needed, to gain more decisive information about the influence of genetic vs. environmental factors in the development of GID.

The authors of the study combine the data from studies of MtF and FtM twins for the statistical analysis. This gives them 9 pairs of identical twins where both twins had gender dysphoria (39%) and 14 pairs of identical twins where only one twin had gender dysphoria (61%). This is contrasted with 21 sets of fraternal twins where only one twin had gender dysphoria (100%). The difference is statistically significant.

This might be problematic since the mechanism that causes gender dysphoria in trans women is probably different from the mechanism that causes gender dysphoria in trans men. The genes are also probably different.

On the other hand the question here is whether or not gender dysphoria is inheirited, so perhaps this works.

Another problem is the possibility of selection bias. It looks like people are over-reporting cases involving identical twins. This might affect comparisons between identical twins and fraternal twins.

In addition, the total size of the group used in their statistical analysis is small and includes disparate groups – males and females, adults and children, people in different countries, and people living in different eras.

In the end, we’re left with weak evidence for a genetic component to gender dysphoria. We can’t prove it, but there is an excellent case for doing more studies in this area.

There is also an excellent case for future studies looking at what factors make one identical twin have gender dysphoria and one not. This seems to be the more common outcome than for both twins to have gender dysphoria.*****

Original Review:

Gender Identity Disorder in Twins: A Review of the Case Report Literature by Heylens G, De Cuypere G, Zucker KJ, Schelfaut C, Elaut E, Vanden Bossche H, De Baere E, T’Sjoen G in J Sex Med. 2012 Mar;9(3):751-7.

 

*Authors of the studies were from Belgium, Canada, Germany, Iran, Israel, the Netherlands, Serbia, Switzerland, the United Kingdom, and the United States. In addition, one author seemed to be from Scandinavia, possibly either Norway or Sweden.

**Using IVF means that the parents were infertile. It might be that the parents were older or that they had something wrong with their reproductive systems. It could be that the parent’s age or fertility problems affected the children rather than the IVF procedure.

***In some cases, it is hard to tell from the title if an article was a study or case report or an article on gender dysphoria that includes information on a case. Then again, the sub-title of this study is “A review of the case report literature,” so maybe they were all case reports.

**** I think the idea that there is a higher tendency in males than females is overstated. There were only 8 pairs of identical FtM twins and I doubt the 2.5% difference in the frequency of FtM versus MtF identical twin pairs who both have gender dysphoria is significant.

***** There may be selection bias in the cases of identical twins from the case reports. However, the clinic studies did find six sets of identical twins. In five of these six pairs, only one twin had gender dysphoria. Specifically, they found four pairs of identical male twins where only one twin had gender dysphoria, one pair of identical female twins where only one twin had gender dysphoria, and one pair of identical twins who were both FtM. So it looks like it is more common for only one identical twin to have gender dysphoria.

Emphases added are mine, including in the quote from the original review of the literature.