What’s the difference between “sex” and “gender”? What does “gender identity” really mean? Secular culture confusedly exalts and affirms a gazillion different form of self-designated “gender-identities,” claiming that men might just be women after all, and vice versa. But they’re not.

One popular pro-LGBT organization refers to biological sex as “what the doctor assigned you at birth” and gender identity as “how you feel on the inside,” with a full (and infinite) “spectrum” of possible points arising between the endpoints of “man” and “woman.” Notice that the objective reality of biological sex is reduced to a medical “opinion,” to be easily brushed aside by anyone who might feel something different on the inside, when compared with one’s bodily existence as either male or female.

The concept of “gender identity,” based solely upon one’s “feelings,” paradoxically leaves unanswered an important question: How is it possible for a man to know what it feels like to be a woman, such that he can possibly perform a self-evaluation that concludes he feels more like a woman than a man?

It’s impossible. It’s impossible to define categorically a certain set of feelings that makes someone a woman (or a man). The gender-identity language then shifts to identification and presentation or expression. I’m a man who identifies as a woman (how? on what basis?). Or, I want to present or express myself as a woman, not a man (based on what?).

Men really have no idea what it “feels like” to be a woman, and vice versa. How many spats between husbands and wives feature that assertion, for example? One’s being a woman or man is inextricably woven into one’s existence as male or female. No one can describe or imagine what it feels like to be a woman apart from a woman’s experience of being bodily female (and the same holds for men). Under examination, the category “gender identity” self-implodes, collapsing in on its own absurdity, leaving behind only the truth that a male’s masculinity and a female’s femininity run much deeper than the mere external sociocultural conventions we might often associate with those terms.

We Are Our Bodies

What are sex and gender, then? As Pope St. John Paul II explained in his 1960 book Love and Responsibility, “sex [being male or female] is a property of the human person.” Subjective consciousness or “self-knowledge” cannot somehow determine one’s maleness or femaleness apart from the body. “How I feel on the inside” does not get the last word.

Note that he does not merely say sex is a property of the body alone, but of the person. This is a crucial element to the thinking he expresses later in the Theology of the Body audiences.

The theology of the body, which is linked from the beginning with the creation of man in the image of God, becomes in some way also a theology of sex, or rather a theology of masculinity and femininity, which has its point of departure here, in Genesis. …Masculinity and femininity express the twofold aspect of man’s somatic constitution…and indicate, in addition, through the same words of Genesis 2:23, the new consciousness of the meaning of one’s body (TOB 9:5).

For St. John Paul II, masculinity and femininity are inseparably linked to the “somatic” (bodily) reality of being male or female—that is, linked to sex, not “gender.” The TOB corpus does not once rely upon the word “gender” (and certainly not the concept of “gender identity”) in its magisterial exploration and explanation of the human person as created by God. Masculine and feminine here do not refer to mere social constructs of what it means to act in a “manly” or “womanly” manner. Rather, masculine and feminine refer to the two ways in which the human person expresses “consciousness of the meaning” of his or her own body.

There is no room here for constructing a “gender identity” separate from the body. The primordial example of one’s authentic self-discovery of sexual (and not “gender”) identity is found in the St. John Paul’s description of the “original solitude” of the first man, Adam, which he experiences after his creation and before Eve’s creation (see TOB 5-7). This is the point at which Adam attains a certain self-knowledge and conscious awareness of his own existence as a person among non-persons—the animals. No “suitable partner” (no other person) exists among the other creatures in Eden.

It seems…that this solitude has two meanings: one deriving from man’s very nature, that is, from his humanity…, and the other deriving from the relationship between male and female. (TOB 5:2).

That is, Adam experiences solitude on two levels—as a person and as a male—even and especially before the existence of woman. Adam is “in search of his own being, as it were; one could say, in search of his own definition; today one would say, in search of his own ‘identity’” (TOB 5:5). This solitude expresses man’s discovery of “his own self-knowledge as the first and fundamental manifestation of humanity” (TOB 5:6). In his “subjectivity,” Adam must discover his own nature not only as a human person but as a male, whose bodily existence expresses his personhood. He is a body—he doesn’t merely have a body. “He is a body among bodies,” yet unlike the other creatures, it is his body “through which he is a person” (TOB 6:3). Adam, in solitude before Eve, “discovers the meaning of his own bodiliness” (TOB 6:4).

The Human Body Expresses and Reveals the “I”

What does all this mean for us, here and now? What St. John Paul II later calls the “spousal meaning of the body” (being made for self-gift either as man or as woman) is something we are all called to discover and understand as the means through which our personhood is expressed in the visible world. There is nothing malleable about the objective truth of our bodily and “person-alexistence as man or woman—it’s a fact that exists regardless of our feelings about that fact. It defines the very meaning of not only our identity (our own “I”) but also of our capacity for self-gift in the visible world.

As a man, for example, I cannot present myself—my “I”—to the visible world as the “self-gift” that is woman. My manly/masculine “I” does not contain womanliness/femininity. I would only cause myself great harm if I somehow misperceived the truth of who I am by erroneously discovering that which my body is not actually expressing to the visible world. (e.g., misperceiving I’m a “man” in a woman’s body).

Instead, just like Adam did in the beginning, we are each called by God to encounter and discover the reality of how God makes us, as man or woman. The only authentic way to honor the truth of how God creates and sustains us is to acknowledge that truth in the visible world. Our bodies are made to accomplish this task for us, in fact.

In almost all cases (apart from some rare but genuine physiological ambiguities), our bodies eloquently speak for themselves in the language of the spousal gift of man to woman and woman to man. We need to learn once again how to listen to our bodies, for our bodies are always speaking the truth about who we are and how God made us.