15 December 2017

Statistics faulty on how many trans- kids grow up to stay trans-?

The National Post recently covered the CBC’s cancellation of a BBC documentary about transgender children (Why CBC cancelled a BBC documentary that activists claimed was ‘transphobic’).  In that coverage, the Post shared claims made by some activists criticizing some scientific studies, but did not apparently fact-check those claims, so I thought I would outline the studies here.  For reference, in a previous post, I listed the results of every study that ever followed up transgender kids to see how they felt in adulthood (Do trans- kids stay trans- when they grow up?).  There are 12 such studies in all, and they all came to the very same conclusion: The majority of kids cease to feel transgender when they get older.

National Post, 13 December 2017
The Post conveyed criticisms alleged about two of those:  “One study of Dutch children, in particular, assumed that subjects had ‘desisted’ purely because they stopped showing up to a gender identity clinic.”  Although unnamed, the claim appears to be referring to Steensma et al. (2013), which followed up on 127 transgender kids.  Of them: 47 said they were still transgender; 56 said they were no longer transgender (46 said so directly, 6 said so via their parents, and 4 more said so despite not participating in other aspects of the study); and 24 did not respond to the invitation to participate in the study or could not be located.  Because all the medical services for transition are free in the Netherlands and because there is only one clinic providing those services, the researchers were able to check that none of the 24 had actually transitioned despite having the opportunity to do so.  Steensma therefore reported that (80/127 =) 63% of the cases desisted.  The alleged criticism is that one should not assume that the 24 who did not respond or could not be found were desisters.  Regardless of whether one agrees with that, the irrelevance of claim is clearly seen simply by taking it to its own conclusion: When one excludes these 24, one simply finds a desistance rate of (56/103 =) 54% instead of 63%.  That is, although numerically lower, it nonetheless supports the very same conclusion as before. The majority of kids cease to feel transgender when they get older.

The other alleged criticism was that a study “cast too wide a net on which children were legitimately displaying gender dysphoria.”  Although also unnamed, this seems to refer to Drummond et al. (2008), which followed up 25 kids assessed in childhood for gender issues: 15 of the 25 received official diagnoses for their gender dysphoria, and 10 were judged to be experiencing the feelings, but to be “subthreshold” for an official diagnosis.  That is, the alleged criticism is that including “subthreshold” cases would water down the results from cases who are formally diagnosed.  The irrelevance of that claim is again easily seen by looking at it directly: Of the 15 kids who received a diagnosis, two continued to be transgender in adulthood (13/15 = 87% desistance), and of the 10 without a diagnosis, one continued to be transgender (9/10 = 90% desistance).  Drummond thus reported their combination, that (22/25 =) 88% desisted.  That is, both the “too wide” net and the narrow net each support the very same conclusion: The majority of kids cease to feel transgender when they get older.

I am personally of the opinion that the studies' authors were correct in their original methods, but the numbers indicate that it simply does not matter.  Even if the criticisms were valid, the studies conclusions would remain the same.

The state of the science is made clear simply by listing the results of the studies on the topic.  Despite coming from a variety of countries and from a variety of labs, using a variety of methods, all spanning four decades, every single study without exception has come to the identical conclusion.  This is not a matter of scientists disagreeing with one another over relative strengths and weaknesses across a set of conflicting reports.  The disagreement is not even some people advocating for one set of studies with other people advocating for different set of studies:  Rather, activists are rejecting the unanimous conclusion of every single study ever conducted on the question in favour of a conclusion supported by not one.

Importantly, these results should not be exaggerated in the other direction either: The correct answer is neither 0% nor 100%.  Although the majority of transgender kids desist, it is not a large majority.  A very substantial proportion do indeed want to transition as they get older, and we need to ensure they receive the support they will need.  Despite loud, confident protestations of extremists, the science shows very clearly and very consistently that we cannot take either outcome for granted.


Drummond, K. D., Bradley, S. J., Badali-Peterson, M., & Zucker, K. J. (2008). A follow-up study of girls with gender identity disorder. Developmental Psychology, 44, 34–45. 

Steensma, T. D., McGuire, J. K., Kreukels, B. P. C., Beekman, A. J., & Cohen-Kettenis, P. T. (2013). Factors associated with desistence and persistence of childhood gender dysphoria: A quantitative follow-up study. Journal of the American Academy of Child and Adolescent Psychiatry, 52, 582–590.

The BBC documentary pulled from CBC is viewable here:

25 June 2017

Dear Dr. James: Could a certain amount of pedophilic interest simply be normal for men?

This question was left as an anonymous comment for last week’s entry, Will there ever be a cure for pedophilia?  But because I receive this question so frequently, thought I'd put it here as it’s own entry...
Dear Dr. James: Could a certain amount of pedophilic interest simply be normal for men? 
Men in prehistoric times who chased after say 9 year old girls would have left behind more descendants than men who chased after 30 year old women for the simple reason that a 9 year old has many more fertile years remaining. When men in primitive societies raid and abduct females from other tribes the most highly prized are the young virgin teens and preteens for the same reason. Essentially what's happening is that men are stealing eggs off other tribes and the females with the most eggs in their ovaries are the young virgins who haven't started reproducing yet.
That comment really has two parts. The first part is a straight-forward question with a straight-forward answer: Yes, typical men do indeed show a certain (very small) amount of response to children—this has been shown repeatedly again in the lab (Blanchard et al., 2009, figures shown below). That pattern of arousal does not indicate being a pedophile, however. Although typical men sometimes respond (a bit) to children, they respond more to older persons, and the most (by far) to adults. That is, typical men strongly prefer adults over children, even if some have some non-zero level of response to children.

The second part is an idea I have heard before, but I am afraid it is based on some false information: Fertility does not start at the beginning of puberty. Indeed, fertility does not start even when menstruation starts (another common misconception). The menstrual cycle begins at an average age of 12.3 to 12.9 (Euling et al., 2008; Finer & Philbin, 2014; Herman-Giddens et al., 1997), whereas a woman’s ovaries don’t start releasing eggs until roughly three years later, on average (Apter, 1980; Metcalf et al., 1983). Although we do occasionally see instances in the media of very young girls becoming pregnant, these are, of course, the exception. Hormone studies show that human fertility starts at the low point of puberty, increasing to peak during the 20s, and decreasing again over the 30s (Ellison, Panter-Brick, Lipson, & O’Rourke, 1993).

That is, a man who focuses his energies on women in their 20s would produce pregnancies than a man who focused those energies on women in their 30s (who are less fertile) or in their teens (and are least fertile of all).

Also arguing against the “kidnap them as girls to get all their subsequent offspring” idea is that it forgets that pedophilia is the preference for children. When such girls become adults and able to bear children, they are no longer attractive to the pedophile. Even though the now-adult could conceive children, the pedophile is more attracted to the girls who cannot. So, once again, the greater the pedophilia, the lesser the chance of successful reproduction.


Apter, D. (1980). Serum steroids and pituitary hormones in female puberty: A partly longitudinal study. Clinical Endocrinology, 12, 107–120.

Blanchard, R., Lykins, A. D., Wherrett, D., Kuban, M. E., Cantor, J. M., Blak, T., . . . Klassen, P. E. (2009). Pedophilia, hebephilia, and the DSM-V. Archives of Sexual Behavior, 38, 335–350.

Ellison, P. T., Panter-Brick, C., Lipson, S. F., & O’Rourke, M. T. (1993). The ecological context of human ovarian function. Human Reproduction, 8, 2248–2258.

Euling, S. Y., Herman-Giddens, M. E., Lee, P. A., Selevan, S. G., Juul, A., Sorensen, T. I. A., . . . Swan (2008). Examination of US puberty-timing data from 1940 to 1944 for secular trends: Panel findings. Pediatrics, 121 (suppl. 3), S172–S191.

Finer, L. B., & Philbin, J. M. (2014). Trends in ages of key reproductive transitions in the United States, 1951–2010. Women’s Health Issues, 24, e271–e279.

Herman-Giddens, M. E., Slora, E. J., Wasserman, R. C., Bourdony, C. J., Bhapkar, M. V., Koch, G. G., & Hasemeier, C. M. (1997). Secondary sexual characteristics and menses in young girls seen in office practice: A study from the Pediatric Research in Office Settings network. Pediatrics, 99, 505–512.

Metcalf, M. G., Skidmore, D. S., Lowry, G. F., & Mackenzie, J. A. (1983). Incidence of ovulation in the years after menarche. Journal of Endocrinology, 97, 213–219.

20 June 2017

The 2017 SEXposium!

Hey, folks!

I just want to give a big shout out and thanks to organizers of this year’s amazing SEXposium!  They brought to Toronto  some really big names in the science of sexincluding Marc Breedlove and Meredith Chivers and otherswho have TED-style talks, available to the public.  It was a great program, the audiences were engaged and invigorating, and it was wonderful to see so many talented students planning to pursue this as a career!  It was a genuine pleasure to participate!

The organizer, Diana Peragine, did an amazing job.  She's a grad student in the Laboratory of Cognitive Neuro-science, Gender, and Health at the University of Toronto. I understand that this is just the second year of this project: So, I'm already pretty excited to see how it shapes up for next year!  This was truly an impressive project on a topic with no shortage of public interest!

James Cantor at the 2017 SEXposium
Royal Ontario Museum, Toronto, Ontario.
For those interested, the slides from my own talk, Pedophilia being in the brain: The evidence & the public's reaction, can be downloaded by clicking here. There was a lot of live tweeting during my talk, and I am grateful for all your comments!

Dear Dr. James: Will there ever be a cure for pedophilia?

Dear Dr. James:

I have two questions I would like answers to. First question: Why is there no cure for pedophilia attraction?  Secondly, will there ever be a cure?  I have read that white matter is one of the problems causing the disorder.  So, why can’t we just add more white matter, for example?  If we, as humans, can solve so many problems, I don't see why we shouldn’t be able to solve this one in some way in the near future.

@fadelsadel via twitter

Hi, @fadelsadel.  Thanks again for letting me share your question: I think a lot of people are interested in knowing exactly the same things!

For your first question: I think it ultimately boils down there not being any funders—either public research agency or private philanthropist—who have taken this on as a goal.  Most people (very understandably) have strong emotions when it comes to this topic, and they fear and avoid any whiff of the stigma surrounding it. However, in my experience, only little education on the topic is needed before most people recognize how much we stand to gain, and how much suffering (nevermind financial expense) stands to be saved.  We need a public health official or a Bill Gates type to recognize what could be done if we (first) just faced down the stigma of discussing this rationally.

For your second question: I could never say never.  It’s amazing to think that it was only 10 years ago that we even established pedophilia to be a neurological phenomenon at all.  Currently, it still looks like pedophilia emerges from atypical connectivity among brain regions that identify/perceive social stimuli as sexy.  If governments and research funders made a serious effort to figure out how the sex response system of the brain worked, then we might be in a better position to know which of the ever-emerging tools from neuroscience could be applied.  Moreover, the more we know about how it develops, the earlier we might be able to detect it, and the earlier something is detected, the easier it is to influence.  I want to add, however, that these are fundamentally important questions of bioethics related to the science of this topic:  Many people have discussed these issues with regard to converting homosexuals to heterosexuals, but not with regard to converting pedophiles or others whose sexual interest pattern (unlike homosexuality) cannot be enacted without risk of harm.

Although it seems logical, just adding white matter isn’t as simple as it might sound.  Brain development starts very early after conception, and it undergoes very many phases ultimately leading to each point in the brain connecting to just the right other point of the brain.  Interestingly, the infant and childhood brain is quite “over-connected.” After childhood, substantial pruning of white matter occurs.  In adulthood, brain cells (the neurons) do not divide and make new brain cells like other types of cells.  The various signals that cells used to determine the direction to grow towards are no longer present in adulthood.  So, the great complication (I predict) will be how to get each of the brain cells to connect to all the corresponding brain cells, even though the rest of the brain is no longer undergoing the series of phases that originally led to its final structure. 

The best analogy I have is that, when it is still batter, we can add chocolate to make it a chocolate cake, but after it’s baked, adding the same ingredient gives us a vanilla cake drizzled with chocolate sauce.  That said, we are outside of my real field of expertise.  This step in figuring out a cure will have to come from a conversation between a real neuroscientist on top of developments in that field and a sex researcher who describes this situation until the neuroscientist says, “Hey, that sounds just like…”.

I don’t know who those people will be or what technology that will be, but I feel confident to saying that such conversations are most likely to happen in place that foster cross-pollination between fields and offer scientists some flexibility outside of a business model, and such places are becoming increasingly rare.

[FOOTNOTE: Just for the record, I’m using the colloquial sense of the word “cure” here, as the writer meant it.  I point this out to acknowledge that there are other people who would emphasize that (1) when someone sexually prefers children, but is neither distressed by it nor poses a risk of harm to anyone because of it, then the person would not receive a diagnosis in the DSM-5 system, and (2) without there being a diagnosis, it is not clear whether one should be referring to a “cure.”]