Friday, 5 June 2015

McHugh's "Surgical Sex" Revisited

In which Dr Paul McHugh's 2004 article Surgical Sex is rebutted by.... Dr Paul McHugh's 2004 article Surgical Sex.

Why did Johns Hopkins stop performing sex reassignment surgery? The obvious reason is that their surgeon left, and wasn't replaced. They now refer patients to other surgeons after assessing suitability. The surgery is now no longer a "research" effort, but part of mainstream medical practice.
But there's more to it than that.

From McHugh's work, Psychiatric Misadventures :
I happen to know about this (sex-reassignment surgery) because Johns Hopkins was one of the places in the United States where this practice was given its start. It was part of my intention, when I arrived in Baltimore in 1975, to help end it.
Verdict first, trial afterwards.

The Meyer study McHugh commissioned in support of his pre-determined aim, and used as the primary evidential basis for the conclusions in Surgical Sex  was, well, it has figures on a scale of -8 to 5 with values of 19. For a scathing critique of just some of the more obvious nonsense that means it should never have passed even the most cursory peer review, due to the ridiculous figures in it, see
Sex Reassignment. Thirty Years of International Follow-up Studies After Sex Reassignment Surgery: A Comprehensive Review, 1961-1991 Friedemann Pfäfflin, Astrid Junge (Translated from German into American English by Roberta B. Jacobson and Alf B. Meier),
Chapter 3: Follow-up studies in chronological order : Meyer & Reter, 1979 Dept. of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
"The tables and figures shared by the authors do not seem serious because after the scoring table a maximum of only eight minus and five plus points can be achieved, but in the results table (p. 1014) a range from -18 to +19 points is given. How these figures came about remains totally in the dark....One asks the question how it came about that a renowned professional publication published such opaque figure material."
Junk Science from the "Dark Age of Psychiatry".

McHugh adduces in support of his secondary thesis, that genes determine sexual identity, an article by Reiner,
Discordant Sexual Identity in Some Genetic Males with Cloacal Exstrophy Assigned to Female Sex at Birth
by Reiner and Gearhart, N Engl J Med. 2004 January 22; 350(4): 333–341.
McHugh writes:

"Reiner concluded from this work that the sexual identity followed the genetic constitution. "

Reiner did no such thing. He stated that sexual identity followed the hormonally-directed path in foetu.
1 in 300 men aren't 46,XY, they do not have a "male" genetic constitution (as McHugh puts it). Some women do. Genes are only important in that they *usually* (not always) cause a specific hormonal environment in the womb.

It's important to make the distinction because hormonal environment during pregnancy can change, resulting in mixed anatomy, part female, part male. It can also be completely out of synch with "genetic constitution", resulting in XY females and XX males.

This explains the situation, and why McHugh's claim that "genetic constitution" dictates "sex identity" is very obviously a misinterpretation of the evidence.
Sexual Hormones and the Brain: An Essential Alliance for Sexual Identity and Sexual Orientation Garcia-Falgueras A, Swaab DF Endocr Dev. 2010;17:22-35 

The fetal brain develops during the intrauterine period in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge. In this way, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation are programmed or organized into our brain structures when we are still in the womb. However, since sexual differentiation of the genitals takes place in the first two months of pregnancy and sexual differentiation of the brain starts in the second half of pregnancy, these two processes can be influenced independently, which may result in extreme cases in trans-sexuality. This also means that in the event of ambiguous sex at birth, the degree of masculinization of the genitals may not reflect the degree of masculinization of the brain. There is no indication that social environment after birth has an effect on gender identity or sexual orientation.

Note that McHugh got it partly right -
"Male hormones sexualize the brain and the mind."
"Having looked at the Reiner and Meyer studies, we in the Johns Hopkins Psychiatry Department eventually concluded that human sexual identity is mostly built into our constitution by the genes we inherit ..."
WRONG - this contradicts the previous statement, that it's hormonal environment that's the issue
" ... and the embryogenesis we undergo."
Correct again.

Moving outside the field of psychiatry, let's look at physical anatomy. If embryogenesis and hormonal environment rather than "genetic constitution" is key, if "male hormones (in the womb) sexualise the brain and the mind" as McHugh says, then there has to be physical, objectively measurable evidence of this.

If genetic constitution is key - as McHugh also says, contradicting himself, it is impossible for "genetic males" to have female brain structures.
If hormonal environment is key, then we'd observe female brain structures in all those with a female sex identity, and only those with a female sex identity, regardless of genetic constitution.
The experiment to determine which is correct is simple.

 A sex difference in the human brain and its relation to transsexuality. by Zhou et al Nature (1995) 378:68–70.
   Our study is the first to show a female brain structure in genetically male transsexuals and supports the hypothesis that gender identity develops as a result of an interaction between the developing brain and sex hormones
Note the date. 1995. Twenty years ago. Nine years before McHugh's article.
In terms of what this means for patients.... here's McHugh again.
"Proper care, including good parenting, means helping the child through the medical and social difficulties presented by the genital anatomy.... This effort must continue to the point where the child can see the problem of a life role more clearly as a sexually differentiated individual emerges from within. Then as the young person gains a sense of responsibility for the result, he or she can be helped through any surgical constructions that are desired. Genuine informed consent derives only from the person who is going to live with the outcome and cannot rest upon the decisions of others who believe they “know best.”
ABSOLUTELY! This applies to both Transsexual and Intersex children. Those who believe they "know best" because of religious conviction or whatever should not be allowed to mandate un-necessary treatment, or prevent necessary treatment. Moreover, as sexual identity is based on biology, and biology is anything but a strict binary, the sexual differentiation may not be binary either. Some will be most comfortable conforming to a binary model, while others will find that model neither comfortable nor appropriate. Similarly, surgical options should be offered, but never required. The patient may be fine with having unusual genitalia - their body, their choice.

 Back to McHugh again...
" I have learned from the experience that the toughest challenge is trying to gain agreement to seek empirical evidence for opinions about sex and sexual behavior, even when the opinions seem on their face unreasonable. One might expect that those who claim that sexual identity has no biological or physical basis would bring forth more evidence to persuade others. But as I’ve learned, there is a deep prejudice in favor of the idea that nature is totally malleable. "
 Again, completely agree in all respects. The problem is that McHugh states that
  1. Sexual Identity results from hormonal factors (true)
  2. Sexual Identity instead results from "genetic constitution" (false)
and also
  1. Sexual Identity always without exception results from biological factors (true)
  2. Sexual Identity in Transsexuals is a "mental illness" with no physical basis (false)
Bottom line:

Male–to–female transsexuals have female neuron numbers in a limbic nucleus. Kruiver et al J Clin Endocrinol Metab (2000) 85:2034–2041
"The present findings of somatostatin neuronal sex differences in the BSTc and its sex reversal in the transsexual brain clearly support the paradigm that in transsexuals sexual differentiation of the brain and genitals may go into opposite directions"


Anonymous said...

This is a good explanation of the study mentioned in the article:


Lauren G

Zoe Brain said...

Corrected link:

Anonymous said...

What makes a women?


Zoe Brain said...

“You can’t pick up a brain and say ‘that’s a girl’s brain’ or ‘that’s a boy’s brain,’ ” Gina Rippon, a neuroscientist at Britain’s Aston University, told The Telegraph last year.

Incorrect-ish. Examination of the cells of the BSTc layer is quite reliable.

No, you can't pick up a brain and determine sex. You need to slice it up with a microtome, and examine the slices with a microscope. Then you can.

An MRI or PET scan on living subjects isn't 100% reliable, unlike that procedure, but still better than, say, examining chromosomes or skeleton.

Zoe Brain said...

Two articles that might help.

First, Fine C1, Jordan-Young R, Kaiser A, Rippon G. - Plasticity, plasticity, plasticity... and the rigid problem of sex

(PDF available here)

Then a critique of this (and other articles in the same vein).

L, Cahill Equal ≠ The Same: Sex Differences in the Human Brain

To make matters worse, studying sex differences in the brain was for a long time distasteful to large swaths of academia. Regarding sex differences research, Gloria Steinem once said that it’s “anti-American, crazy thinking to do this kind of research.” Indeed, in about the year 2000, senior colleagues strongly advised me against studying sex differences because it would “kill” my career
“But wait,” argue the anti–sex difference authors, “the brain is plastic”—that is, molded by experience. One group of authors uses the word plasticity in the title of their paper three times to make sure we understand its importance. (As someone who has studied brain plasticity for more than 35 years, I find the implication that it never occurred to me amusing.) By the plasticity argument—also made explicitly by neuroscientist Lise Eliot in her book Pink Brain Blue Brain—small sex differences in human brains at birth are increased by culture’s influence on the brain’s plasticity. Eliot further argues that we can avoid “troublesome gaps” between the behaviors of adult men and women (a curious contradiction, by the way, of the view that there are no behavioral differences between the sexes) by encouraging boys and girls to learn against their inborn tendencies.

It is critical to understand where the fallacies in this argument lie. First, it is false to conclude that because a particular behavior starts small in children and grows, that behavior has little or no biological basis. One has only to think of handedness, walking, and language to see the point. Second, this argument presupposes that human “cultural” influences are somehow formed independent of the existing biological predispositions of the human brain. But third, and most important, is the key fallacy in the plasticity argument: the implication that the brain is perfectly plastic. It is not. The brain is plastic only within the limits set by biology.

Zoe Brain said...

The presence of biological limits to plasticity—and hence the presence of limits to how much experiences can affect the brain—is perhaps made most clear in elegant studies by J. Richard Udry. In his important but underappreciated paper entitled “Biological Limits of Gender Construction,” Udry examines the interaction between two factors—how much a mother encouraged her daughter to behave in “feminine” ways, and how much the daughter had been exposed to masculinizing hormonal influences in the womb—on how “feminine” the daughter behaved when she was older. The figure below illustrates the key findings.

The graph illustrates that, indeed, the more mothers encouraged “femininity” in their daughters, the more feminine the daughters behaved as adults, but only in those daughters exposed to little masculinizing hormone in utero. Crucially, the greater the exposure to masculinizing hormonal effects in utero (the progressively lower lines), the less effective was the mother’s encouragement, to the point where encouragement either did not work at all (line with squares) or even tended toward producing the opposite effect on the daughters’ behavior (line with diamonds).

All those wishing to understand sex influences on the human brain need to fully grasp the implications of the animal literature, and then think about the Udry data, which captures an incontrovertible fact from brain science: Yes, brains are plastic, but only within the limits set by biology. It is decidedly not the case that environmental experience can turn anything into anything, and equally easily, in the brain. The specious plasticity argument invoked by anti–sex difference authors appears to be just a modern incarnation of the long-debunked “blank slate” view of human brain function, the idea that all people’s brains start out as blank slates, thus are equally mold-able to become anything through experience