Since the publication of Time's recent cover story "The Transgender Tipping Point," there has been a spate of conservative op-eds in retort, including ones featured in the Chicago Sun-Times and the Wall Street Journal, and online on conservative websites such as The Federalist. The attacks follow a predictable set of talking points that rely on the reader having no scientific knowledge of the issue. However, when examined from a perspective of peer-reviewed medical consensus and law, these talking points fail utterly.
"Transgender people are by definition mentally disordered."
The organization responsible for defining what is and is not a psychiatric disorder, the American Psychiatric Association, has this to say about the matter (via the DSM-5):
It is important to note that gender nonconformity is not in itself a mental disorder. The critical element of gender dysphoria is the presence of clinically significant distress associated with the condition.
In short, the people who wrote the definition of "psychiatric disorder" categorically reject the statement that a transgender identity is intrinsically disordered.
"Chromosomes always define sex and gender."
Unless you have complete androgen-insensitivity syndrome (CAIS), or 5-alpha-reductase deficiency, or Swyer syndrome, or genetic mosaicism, or 17-beta-hydroxysteroid dehydrogenase III deficiency, or progestin-induced virilisation, or prenatal exposure to diethylstilbestrol, or any of a wide range of endocrine-based variations that cause a person person to have chromosomes that don't match their primary sexual characteristics or gender identity.
A woman with XY chromosomes developed as a normal woman, underwent spontaneous puberty, reached menarche, menstruated regularly, experienced two unassisted pregnancies, and gave birth to a 46,XY daughter with complete gonadal dysgenesis.
"Transgender identities are a delusion."
A transgender identity does not fit the psychiatric definition of "delusion," nor has it ever been encoded as such in the DSM.
"There is no evidence that you can have a female brain in a male body or vice versa."
There is very strong evidence of the biological origins of transgender identities, actually. From Chung and Auger, European Journal of Physiology, 2013:
Gender-dependent differentiation of the brain has been detected at every level of organization -- morphological, neurochemical, and functional -- and has been shown to be primarily controlled by sex differences in gonadal steroid hormone levels during perinatal development.
From Swaab and Bao, Neuroscience in the 21st Century, 2013:
Gender identity (the conviction of belonging to the male or female gender), sexual orientation (hetero-, homo-, or bisexuality) ... are programmed into our brain during early development. There is no proof that postnatal social environment has any crucial effect on gender identity or sexual orientation.
From Jürgensen, et al., Journal of Pediatric Endocrinology and Metabolism, 2010:
There is strong evidence that high concentrations of androgens lead to more male-typical behavior and that this also influences gender identity.
Transgender identities appear to be a genuine mismatch between primary sexual characteristic and neurological phenotypes during prenatal development.
"Dr. Paul McHugh, retired from psychiatry at Johns Hopkins Hospital..."
Dr. McHugh is a self-described orthodox Catholic whose radical views are well documented. In his role as part of the United States Conference of Catholic Bishops' review board, he pushed the idea that the Catholic sex-abuse scandal was not about pedophilia but about "homosexual predation on American Catholic youth." He filed an amicus brief arguing in favor of Proposition 8 on the basis that homosexuality is a "choice." Additionally, McHugh was in favor of forcing a pregnant 10-year-old girl who had been raped by an adult relative to carry to term.
If you want a detailed analysis of how Dr. McHugh has misrepresented data, rigged studies, left out significant details in his research, and is nothing more than a poorly regarded fringe element in his own field, you can read about it here, here, here, here, here, and here. No secular medical or mental-health organization agrees with him. Even his own (former) department denounced his stance in testimony before the Maryland Senate. Court cases looking at transgender medical issues have found his work unpersuasive.
In short, Paul McHugh is the Mark Regnerus of transgender issues.
"The statistics on transgender suicide rates prove they're mentally unstable."
It is accepted within medicine, mental-health, and sociology communities that these adverse statistics reflect a combination of minority stress and lack of access to affirming health care. When given access to supportive environments and medical care, quality of life for transgender women (including mental health) is not significantly different from the general population.
"Those people need mental-health counseling to fix their identity, not medical intervention."
Every major medical and mental-health organization in the U.S. officially supports access to affirming care. This is because decades of peer-reviewed research have shown it to be the most effective way of dealing with gender dysphoria.
It has overwhelmingly demonstrated that affirming medical care is effective and of material clinical benefit to individuals with gender dysphoria. Follow-up studies have shown an undeniable beneficial effect of sex-reassignment surgery on postoperative outcomes such as subjective well-being, cosmesis, and sexual function (DeCuypere et al., 2005; Gijs & Brewaeys, 2007; Klein & Gorzalka, 2009; Pfafflin & Junge, 1998). GRS has also been found to lead to a quantitative decrease in suicide attempts and drug use in post-operative populations (C. Mate-Kole et al., 1990). In studies where affirming care was denied, patients showed significantly worse outcomes (Ainsworth and Spiegel, 2010; C. Mate-Kole et al., 1990).
Additionally, counseling to change gender identity has been found to be both ineffective and potentially harmful. The foremost body of medical and mental-health experts on transgender care, WPATH, has this to say about changing people's gender identities:
Treatment aimed at trying to change a person's gender identity and expression to become more congruent with sex assigned at birth has been attempted in the past without success (Gelder & Marks, 1969; Greenson, 1964), particularly in the long term (Cohen-Kettenis & Kuiper, 1984; Pauly, 1965). Such treatment is no longer considered ethical.
In 2012, as a result of past failures and the harms observed, the American Psychoanalytic Association issued the following position statement on attempts to change a person's gender identity:
Psychoanalytic technique does not encompass purposeful attempts to "convert," "repair," change or shift an individual's sexual orientation, gender identity or gender expression. Such directed efforts are against fundamental principles of psychoanalytic treatment and often result in substantial psychological pain by reinforcing damaging internalized attitudes.
Courts are recognizing this as well. Federal courts in New Jersey and the Ninth Circuit have agreed that the claims of the proponents of reparative therapy for gender identity and sexual orientation are not supported by science. The district court in New Jersey is also allowing plaintiffs to sue for damages as a result of harm caused by reparative therapy.
Simultaneously, a new Williams Institute study on mental-health counseling for sexual minorities shows that those who sought mental-health counseling from a religious or spiritual adviser (who is more likely to urge them to change) were more likely to subsequently attempt suicide than those who sought no treatment at all.
"It's madness that we could be losing!"
Beyond the fact that punching down in our society is generally seen as bad form, it is because medicine and mental-health organizations follow peer-reviewed research when developing policy. Thankfully, courts in turn defer to actual experts on the matter, not to ideologues, people who falsify their research, or pundits. It all stems from the fact that the vast preponderance of the actual scientific evidence contradicts right-wing talking points on transgender issues.