When the great postmortem on our society of delusions has been written—as it undoubtedly will, because human nature does not change, and biological realities no more than gravity or the phases of the moon are bound to heed what we may say about them—there will be a large category of works by strong-minded men and women that shouldn’t have had to be written. Works on the sexes will be paramount among them, for instead of using the far-reaching cultural and scientific means at our disposal to revel in the beauty of the sexes, male and female, we must instead defend the very idea that there are sexes at all. At the same time we must defend our minds and our children’s minds from the incoherent claim that, although “male” and “female” are supposed to be arbitrary terms devised by “society” with ill intent, a person can actually be a male born in a female body, or vice versa, and, what is more, a child as young as three can penetrate the mystery of this incoherence. It is like saying that Napoleon does not exist, you are Napoleon, and you knew that you were Napoleon shortly after you stopped wearing diapers.

Ryan Anderson has written one of those books. When Harry Became Sally: Responding to the Transgender Moment is thoroughly researched, relentlessly logical, sensitive to the needs and the confusions of people who wish—or believe they wish—they were members of the other sex, and filled with the startling claims of the activists and with the stories of people abused by doctors all too quick to drug and mutilate. Yet the book is hopeful, because in point of fact the transgender house is built of sand, and only social coercion from on high can prevent ordinary people from noticing it and saying what is obvious. It is a brilliant book in a bad time.

Let me focus on four errors that Anderson, a senior research fellow at The Heritage Foundation and the founding editor of the online journal the Public Discourse, scouts and, with firmness and temperance, exposes as shallow, illogical, and utterly inconsistent with what we know, both from biological investigation and from common observation.

The first is that sex is “assigned,” as it were arbitrarily, as if you might put a pink or a blue wristband upon the newborn baby in the hospital, on a whim. Related to this error is the notion that sex is a superficial thing, a matter of a few organs down below. On the contrary: sex is the means by which sexed species survive:

Sex as a status—male or female—is a recognition of the organization of a body that has the ability to engage in sex as an act. More than simply being identified on the basis of such organization, sex is a coherent concept only on the basis of that organization. The fundamental conceptual distinction between a male and a female is the organism’s organization for sexual reproduction.

The sexes as such are for one another, in their unique cooperative function, which is the bringing of new human beings into the world. There is no third sex—not even clergymen, as George Bernard Shaw jested. There is no sexual spectrum (Anderson deals with the exceedingly rare cases in which a genetic defect results in someone’s having a latent or ambiguous sex; to say that these are merely normal variations is rather like saying that the human race is not essentially two-legged, because some people are born with one leg or none). “And this really isn’t controversial,” writes Anderson.

Sex is understood this way across species. No one finds it particularly difficult—let alone controversial—to identify male and female members of the bovine species or the canine species. Farmers and breeders rely on this easy distinction for their livelihoods.

Only man can have a stake in obfuscation.

* * *

But even so, aren’t the distinctions trivial? If they were trivial, one might ask why all the need then for amputations, pin-on prostheses, plastic surgery, sterilization, and hormone pumping? But the distinctions are not trivial. As Anderson shows, citing what we know from genetics, physiology, and neurology, we are sexed beings all the way down to the cell, and, from instructions encoded in the zygote, up to every organ and their interrelations, including the brain. It is imperative that physicians and psychiatrists know this. A man’s typical metabolism is not a woman’s. A woman’s bones are not the same as a man’s. Diseases afflict the sexes at different rates and in different ways, and this is why, Anderson notes, medical researchers must now separate their results for sex. Surgeons know it, too: the woman’s heart is smaller than the man’s and presents its own array of issues to deal with. Feminists themselves long complained that men and not women were taken as the paradigmatic recipients of medical care. Yet we are now to believe that some plastic surgery and some influx of artificially administered hormones or suppressors of hormones can magically work a fundamental and complete change.

Which brings me to a second error that Anderson exposes, that “sex” and “gender” are independent of one another. We have long heard from feminists that “sex” is biological, but “gender” is social, and since it is social, it is merely a matter of custom; though now, as Anderson notes, citing gender theorist Judith Butler, some people say that sex itself is a social construction, but that gender, what you feel about yourself, is fundamental and immutable. That is complete madness. Try to apply it to any of your other bodily systems beside the sexual; try saying that your stomach, liver, bladder, intestines, and the entire physical apparatus for converting food into energy and nutrients are socially constructed, but your taste for poached eggs is fixed, innate, and absolute. Anderson argues, correctly, that our social lives are expressions of our biological being: we are, biologically, the kinds of creatures that form the kinds of societies we form:

Human beings are creatures of nature and of culture, but a healthy culture does not attempt to erase our nature as male and female embodied beings. Instead, it promotes the integrity of persons, in part by cultivating manifestations of sex differences that correspond to biological facts. It supports gender expressions that reveal and communicate the reality of our sexual nature.

* * *

We can believe otherwise only if we adopt what Anderson, following his teacher Robert P. George, has called a “new Gnosticism.” This is the belief that the “real self” is something free-floating, maybe three feet over your head and two feet to the right, which uses the body as a mere instrument for procuring its desires. But “if a soul has an inner sense of something, it is of and through the body,” explains Anderson. “Souls aren’t radically detached from bodies; they are the principle that informs them, organizes them, and grounds their root capacities.” I cannot know what it is like to be a bat, says Anderson, taking his cue from the philosopher Thomas Nagel, because I am not a bat. I am a man, and therefore cannot know what it is like to be a woman. What Bruce Jenner wants instead is that others perceive him as a woman; he is out of kilter with the reality of his body, and he demands that others join in. Nor is there any evidence that “transgender” people as a group have brains that are innately different from members of their own sex as a group:

There are no brain studies demonstrating “predictive power” in any of the biological differences examined, and this lack of predictive power is a serious weakness for a scientific theory. So there is no warrant for the claims in popular media outlets that biological differences located in the brain determine gender identity.

* * *

Therefore, to move to the third error, there is no reason to suppose that a mere child can know what his “real” gender is. Anderson asks a form of this question again and again: “On what other subject is the assertion of a two-year-old ‘no less valid’ than that of an older child or an adult?” When we examine what a child means when he or she says he is “really” of the other sex, we see that the child is either interpreting things according to superficial, inexperienced knowledge of the sexes, or is responding to the actions of adults—sometimes to abuse by adults. In other words, the child’s notion of the other sex is, if anything, “socially constructed,” and it tends to be shallow and full of mistakes.

Sometimes a boy, Anderson shows, has an unusually low “activity level,” which depends upon his metabolism, environment, and general temperament, and this may lead him to shy away from roughhousing. He may then prefer, for a while, to play with the girls. This isn’t cause for concern. It doesn’t actually mean anything, unless others force the issue: his peers, by abusing him, or our new and improved monsters in social work, who do worse, and tell him that he might “really” be a girl. No one tells him that he is going through a stage, and that he will very possibly grow to like football. As Anderson shows, 80 to 95% of children with serious gender dysphoria grow out of it: their minds come into accord with their bodies.

Sometimes all it takes is a parent who shows the boy—and we are far more frequently speaking of boys than of girls—that there’s a wide range of ways in which his boyhood is made manifest, and so he is a real boy after all. The boy who can’t stand football has read everything on World War II. The boy who is bored by war stories likes to draw maps of the United States. The boy who can’t draw likes to spend his afternoons tinkering with machines. The boy who doesn’t care for machines wanders the woods with his dog, searching for new discoveries. I have spoken with a young man who cared nothing for sports and for what he considered to be the typically masculine things, who was, in his bearing, his speech, and his rather forceful encounters with others, masculine to the last drop of his blood; yet he was surprised and gratified when I told him so, and told him also that it was obvious.

* * *

That brings me to my final point. No politically-moved violation of reality can be harmless, and Anderson shows the harm in many ways and at many levels. We have what anyone in his right mind would call, and shall call, child abuse, on a colossal scale. We have the coercion of ordinary people, evident in punitive speech codes. We have a mandated dismissal of concerns for the safety of women and girls in bathrooms and locker rooms, and the loss of female-segregated sports teams. We have the perpetuation of, and professional participation in, a severe mental illness: for my perception that I am “really” a girl is like a thin girl’s perception that she is “really” fat, or an attractive woman’s perception that she is “really” ugly, or any other tangle of thoughts and obsessions that are not in accord with reality. If sanity is the adaequatio mentis ad rem, what we have in the transgender movement is an attempt to coerce reality to fit someone’s imagination, and since reality resists the coercion, there can never be an end to the attempt. Nothing will suffice.

When it comes to speaking the truth, Anderson yields not a millimeter. When we deal with persons, he reminds us always to be merciful, and to try to understand what may underlie the delusion. Here I’ll end with an observation that is implicit in this superb and honest book. If there are boys who long to be girls, and girls who long to be boys, it is less because of some reality they know about than because of a reality they have been taught to hate. Men and women in our time have very little good to say about the opposite sex as such, and we should not attribute their acerbity to ingratitude alone. The fact is: men and women have always abounded in ways of making miserable the lives of the other, especially in the aftermath of the sexual revolution. Bad things have become the norm. So we should expect in the near future that more young people, not fewer, will respond in irrational and destructive ways to the poisonous disaffection, suspicion, resentment, and contempt that now dominate the converse of the sexes with one another. May Ryan Anderson’s When Harry Became Sally help lead us back from this self-ruination.