Certainly I feel the same way about my own sexuality. My gender performance is fluid and depends on audience and situation—it's a rhetorical choice, right?—but my sexuality is relatively fixed and has been for as long as I remember: I am bi with a huge swing towards same-sex attraction.
So, I imagine, must be the transgendered condition and so these young men (and what few young women I've archived, a data set if you will that's much smaller in number and size) report—not that they chose to be transgendered or wanted to be but simply were, just as I am bi/mostly gay.
This, of course, has been a debate that has raged on for years—in both directions. In 2004, Vernon A. Rosario reminded us of the ebb and flow of differing conceptions of social construction:
Sandy Stone's 1991 essay, "The 'Empire' Strikes Back: A Posttranssexual Manifesto," was a rallying cry for a new generation of transgender activists and theorists. She called on transgenders to tell their full stories and not the stereotyped clinical narrative required by the gender reassignment gatekeepers in the medical profession. This meant proclaiming an identity as transgendered rather than following the medical expectation to discard a past gendered history and pass as either male or female. A new generation of transgendered theorists deployed antiessentialist, feminist, and queer theory to further flesh out the "post" in fin de siècle transgender ontology. Susan Stryker, in the introduction to the groundbreaking transgender issue of GLQ, fully embraced a performative/discursive model of queer, transgender identity. For Stryker, queer transgenderism was a radical, antiheteronormative praxis of self-transformation through performance—not only of gender but of sexuality and anatomy.
Other theorists have been critical of the aleatory quality of transgender identity in these performative models and have returned to a certain ineluctable materiality of the body and sex, as well as an irreducibility of gender. Even at the risk of falling into a somatic determinism and gender essentialism, Jay Prosser examines the gender experience of transsexuals and the real, poignant ways in which gender identity maps onto anatomy. Prosser aggressively wrestles with the discursive theory of Judith Butler and, more broadly, with the queer theory appropriations of trans identity. Prosser is particularly critical of Butler's reluctance to grapple with the materiality of the body and with her repeated "deliteralization of sex." Prosser points out that transgenderism is exploited in this queer analysis of sex/gender as a subversive denaturalization of sex; however, the actual embodied gender experience of many transsexuals is delegitimized if we collapse sex into gender. As Prosser succinctly puts it, "Gender Trouble uses transsexuality to exemplify not the constitutive significance of somatic feeling but the reverse, the phantasmatic status of sex."
So the technology of T-therapy (and all prescription medications and their delivery systems are technological in nature) is a way—as I read these diaries—of creating social constructs of gender that match an internal condition that at least feels innate. That gets into the difficult question of what natural means, if anything, which is well beyond the scope of this essay.