Sex discrimination demands particular kinds of behavior from one sex, but prohibits the same behavior from the other sex.[i] For example, wearing dresses is ok, but only for females; engaging in sexual relations with females is ok, but only for males. Legal prohibition against sex discrimination encompasses the social policing of both homosexuality[ii] and sex-role (or gender) non-conformity.
Instead of isolating gender non-conforming and gender dysphoric people as a disordered class of persons whose defining characteristic is their departure from normative sex role behavior or appearance, we should recognize enforcement of sex role limitations as universal violations of our human rights—even when they are supported by medical professionals.[iii],[iv],[v] Considering gender dysphoria on an individual level, as special kind of medical condition, evades examination of the oppressive psychological effects of mutually exclusive sex roles. This is particularly disturbing when the suggested medical treatment for gender dysphoria causes sterilization, infertility, and other physical complications.
Sex discrimination as legal strategy can be leveraged by anyone, not just female plaintiffs. It attacks a wide range of sex-role discrimination while simultaneously avoiding the pitfalls of both trivializing biological sex and reifying sex roles by privileging self-identified sex (or gender identity) over biological sex.
The 6th Circuit[vi], the 9th Circuit[vii], and the 11th Circuit[viii] Federal Courts of Appeals, and the EEOC[ix] have all issued decisions affirming the use of a Title VII sex discrimination theory to protect people who understand themselves as transsexual and/or transgender:[x]
“…[a] complaint of discrimination based on gender identity, change of sex, and/or transgender status is cognizable under Title VII…”
This is the most effective and sustainable legal strategy with the strongest precedent.[xi] It protects all gender non-conforming people without forcing them to claim a special kind of “gender identity,” that they are suffering from a special medical condition, or that they are members of a special group called “trans.” Sex discrimination as legal strategy can be used to protect females, gays and lesbians, and gender non-conforming people including transsexuals from the tyranny of compulsory heteronormativity– the principle evil we aim to deconstruct.
[i] “An employer who objects to aggressiveness in women but whose positions require this trait places women in an intolerable and impermissible Catch-22: out of a job if they behave aggressively and out of a job if they do not. Title VII lifts women out of this bind.”
Price Waterhouse v. Hopkins (490 U.S. 228, 251). http://www.law.cornell.edu/supct/html/historics/USSC_CR_0490_0228_ZO.html
[ii] Onacle v. Sundowner Offshore Services (523 U.S. 75). http://www.law.cornell.edu/supct/html/96-568.ZO.html
[iii] See the History of Psychiatry & Homosexuality: http://www.aglp.org/gap/1_history/
[iv] See also the history of lobotomies: “The lobotomy was first performed on humans in the 1890s. About half a century later, it was being touted by some as a miracle cure for mental illness, and its use became widespread; during its heyday in the 1940s and ’50s, the lobotomy was performed on some 40,000 patients in the United States, and on around 10,000 in Western Europe. The procedure became popular because there was no alternative, and because it was seen to alleviate several social crises: overcrowding in psychiatric institutions, and the increasing cost of caring for mentally ill patients.”
http://scienceblogs.com/neurophilosophy/2007/07/24/inventing-the-lobotomy/
[v] See also: Psychiatric Misadventures by Paul R. McHugh. http://www.lhup.edu/~dsimanek/mchugh.htm
[vi] Smith v. City of Salem, Ohio, 378 F. 3d 566 – Court of Appeals, 6th Circuit 2004. http://scholar.google.com/scholar_case?case=988234023344471066&hl=en&as_sdt=2&as_vis=1&oi=scholarr
[vii] Schwenk v. Hartford, 204 F. 3d 1187 – Court of Appeals, 9th Circuit 2000. http://caselaw.findlaw.com/us-9th-circuit/1452083.html
[viii] Glenn v. Brumby, 663 F. 3d 1312 – Court of Appeals, 11th Circuit 2011. http://scholar.google.com/scholar_case?case=16555670383261317325&hl=en&as_sdt=2&as_vis=1&oi=scholarr
[ix] Macy v. Holder, Appeal No. 0120120821 http://www.eeoc.gov/decisions/0120120821%20Macy%20v%20DOJ%20ATF.txt
[x] See additioan, independant analysis here: http://lawprofessors.typepad.com/laborprof_blog/2013/01/the-eeoc-on-transgender-employees-and-sex-discrimination.html
[xi] Yes, I am arguing in favor of formal legal equality (exception: physical and/or biological sex difference)! I would much rather be forced to wear a unisex uniform at work–such as khaki pants and white collared shirt– than to be subjected to awful the dress code that Darlene Jespersen was in this case:
Jespersen v. Harrah’s Operating Co., Inc., 444 F. 3d 1104 – Court of Appeals, 9th Circuit 2006. http://scholar.google.com/scholar_case?case=13073805400077839878&hl=en&as_sdt=2&as_vis=1&oi=scholarr
“Harrah’s policy required all women to wear heavy makeup applied in exactly the same way every day, to match a photograph held by the supervisor.
On April 14, 2006, in a 7-4 ruling, an en banc panel of the Ninth Circuit Court of Appeals upheld the validity of the Casino’s grooming policy. The court said that while some sex-differentiated workplace rules may be discriminatory, in this case, the grooming standards did not reinforce negative stereotypes about women and the plaintiff in this case had failed to present evidence that the policy posed greater burdens for women than for men. Two judges filed dissenting opinions. With regard to the sex stereotyping argument, Judge Harry Pregerson disagreed with the majority, stating that the makeup requirement was based on “a cultural assumption – and gender-based stereotype – that women’s faces are incomplete, unattractive, or unprofessional without full makeup.””
http://www.nclrights.org/site/PageServer?pagename=issue_caseDocket_jespersen
Sex matters. 
“Major psychiatric misdirections often share this intimidating mixture of a medical mistake lashed to a trendy idea. Any challenge to such a misdirection must confront simultaneously the professional authority of the proponents and the political power of fashionable convictions. Such challenges are not for the fainthearted or inexperienced. They seldom quickly succeed because they are often misrepresented as ignorant or, in the cant word of our day, uncaring.”
from Psychiatric Misadventures by Paul R. McHugh
http://www.lhup.edu/~dsimanek/mchugh.htm
[…] Sex discrimination as legal strategy […]
[…] SEX DISCRIMINATION AS LEGAL STRATEGY Sex discrimination demands particular kinds of behavior from one sex, but prohibits the same behavior from the other sex.[i] For example, wearing dresses is ok, but only for females; engaging in sexual relations with females is ok, but only for males. Legal prohibition against sex discrimination encompasses the social policing of both homosexuality[ii] and sex-role (or gender) non-conformity. […]