(Excerpt lifted from "The Right to Be Yourself?" by Douglas Farrow at First Things Blog.)
What do we mean by “gender”? If we take “gender” as a synonym for “sex” (G1),
 we may say something like this: The sexed nature of our bodies matters 
because our bodies themselves matter. “Man is as much body as soul,” to 
quote Tertullian, and as such the body of any human person must be taken
 with full seriousness as an intrinsic, identifying feature of the 
person. That is one reason Tertullian, like Paul, has so much to say 
about the resurrection of the body.
Suppose, however, we do not 
take “gender” as a synonym for “sex,” but use it rather by extension to 
refer to the expectations that quite naturally, if somewhat differently 
in different societies, become attached to the two sexes (G2).
 Used thus, the word becomes more problematic or the concept more 
controversial. Where reference is made to established social roles—the 
usage here is generally adjectival, as in “gender expectations”—the term
 may be politicized as an attack on or a defense of those expectations 
or those unable or unwilling to conform to them. Here, there may 
sometimes be agreement that gender is not in fact crucial to 
identity; that identity is not or ought not to be over-determined by 
sex-based social expectations. Of course there will also be many 
disputes about whether or when identity is being enhanced or distorted 
by conformity or non-conformity to common expectations. This usage 
raises the question of how far identity is self-determined and how far 
it is determined by others. To this question also we will return.
More
 problematic yet is “gender” as used in the expression “gender identity”
 (GI). It is too little noticed—even by eminent people in eminent 
universities, rolling out policies that turn on this expression—that 
“gender” here remains undefined. GI is defined. In the words of the 
Ontario Human Rights Commission, for example, GI is “each person’s 
internal and individual experience of gender.” But “gender” itself, in 
this context, is not defined. We might suppose it to be the person’s sex
 (G1), or the person’s sex considered in relation to social expectations (G2),
 but we would be mistaken. As the Commission goes on to say, GI “is a 
person’s sense of being a woman, a man, both, neither, or anywhere along
 the gender spectrum.” That is not G1 and it is not G2. It is something else, but what?
Now, if we were content to say that GI is one’s sense of being male or female, we wouldn’t need to specify a third meaning, a G3. G1
 would do nicely. Or if we were content to say that GI is one’s own 
alternative to society’s sense of what it means to live properly as a 
male or female, again we wouldn’t need a G3. G2 
would do nicely. Either way, GI would specify something about our 
personal psychology. It would specify our internal, subjective response 
to something objective and externally accessible: either the kind of 
chromosomes we have, or the way society handles people with that set of 
chromosomes. That would be to miss the whole point, however, of talking 
about GI. Talk about GI is intended to break down the male/female binary
 as an objective referent for law and public policy.
GI, in other 
words, is not merely a subjective response to being male or female, nor 
to some collective determination of what maleness or femaleness entails 
socially. GI, as the Commission says, is our sense of being 
male or female, or partly male and partly female, or entirely male and 
entirely female (a Chalcedonianism of the sexes?), or neither male nor 
female. The “neither” is crucial, because it is precisely here that the 
binary begins, not only to break down, but to disappear. And when it 
does disappear, G3 turns out to be—the self in its absolute autonomy over the body.
 Gender identity (GI), then, is simply the story the self tells itself 
about its body, and gender expression (GE) is the acting out of that 
story, the laying down of public and/or private markers, whether 
physical or linguistic or behavioral, that signify the self’s exercise 
of autonomy over the body.
G1 we cannot deny outright, 
though we may fight against it by describing it (with the Commission) as
 something “assigned at birth,” as if it were no more than an arbitrary 
label imposed on us by society in suppression of our autonomy. This, of 
course, is to take an objection made, sometimes fairly, against 
over-rigid forms of G2 and to extend it backwards, altogether implausibly, to G1.
 That move is highly telling. For it underscores the fact that the whole
 business rests on a radically Cartesian, perhaps even a Gnostic, 
mind/body dualism. Which is to say: We will only come round to positing G3 if we have first set at odds the mind and the body, or at least determined that man is not as
 much body as he is soul. And if man is not as much body as he is soul, 
if indeed the self is the self apart from the body and even over against
 the body, if identity is determined by the mind—or perhaps we should 
say, the will—alone, then a number of things follow. I will mention just
 two of them.
First, authentic naming is, and can be, only 
self-naming. Both surnames and first names can and, on this reasoning, 
probably should be given up in exchange for self-selected names. Why 
stop with a preferred first name policy? Surnames don’t specify sex or gender (G1)—that
 is, chromosomes—but they do specify genes. They testify to derivation, 
to givenness, to what is inherited not chosen, every bit as much as do 
first or “given” names. The only reason not to give them up is that it 
would wreak havoc with law and public policy, generating in effect a 
nation of bastards, which, as Rousseau observed, would mean the end of 
the State itself.
Second, then, if authentic naming or identifying
 is a strictly private, self-governed enterprise, what is there that is 
truly public? If my public persona is entirely under my control, and if I
 can die to my old self and rise to my new self any time I choose and in
 whatever manner I choose, and if indeed I am not to be burdened by my 
old “dead” name, as the Dean of Law says, in what sense is my persona 
public? What, for that matter, happens to the rule of law? If Dave 
becomes Renée, can Renée leave Dave’s crimes behind as well as Dave’s 
name? That is worth pondering, as Carl Trueman has pointed out.
 It is one thing to ask whether the star of the McGill Redman can become
 the star of the McGill Martlets, another thing to ask whether Dave the 
rapist can return as Renée the ravishing.
There is a medieval analogue to this question, arising from the identity change that is Christian baptism. Against the charge that, if baptism really did remit all punishment due to sin, “it would be unjust, after baptism, to hang a thief who had committed murder before,” Thomas Aquinas replies that “although a murderer is freed by baptism from his debt of punishment in respect of God, he remains, nevertheless, in debt to men” (ST 3.69.2). Here he assumes, of course, that however profound—eternally profound!—the change wrought by baptism, in which the “old self” is crucified with Christ and a new self emerges, the person who is this self remains one and the same. He therefore cannot escape his obligations to man, even if that obligation be to put his head in a noose. 
 
