Is gender a biological reality?

Question 12027

Whether sex is a biological reality or a social construct has moved from academic seminars to primary schools in about two decades, which is remarkably fast for an idea that reverses something humanity has assumed for all of recorded history. It is now treated in many settings as established fact, with dissent marked down as bigotry or ignorance.

That should make us want to examine the claim rather than assume it. Is it actually true? And what does the evidence, biblical and otherwise, support? Those are fair questions, and asking them is not an act of aggression against anybody.

What Scripture says about how we are made

The foundational statement is Genesis 1:27: “So God created man in his own image, in the image of God he created him; male and female he created them.” The Hebrew terms zakar and neqevah refer to the physical realities of maleness and femaleness. There is no spectrum language and no hint that the categories are negotiable.

Jesus treated the same verse as decisive when He was asked about marriage: “He who created them from the beginning made them male and female” (Matthew 19:4). He did not say that people identify as male and female, nor that culture assigns these roles. He grounded it in a creative act.

Scripture also refuses to separate the person from the body. The body is not packaging around the real self. It is integral to being human, it will be raised (1 Corinthians 15:42-44), and the incarnation itself is God taking a body rather than avoiding one.

The claim that sex and gender are separable

The distinction between biological sex and gender identity is not an ancient insight. It emerged in the mid twentieth century, largely through the work of clinicians and theorists who proposed that a person’s internal sense of being male or female could be independent of the body.

The most famous attempt to demonstrate this ended catastrophically. David Reimer, raised as a girl after a surgical accident in infancy, never accepted the identity assigned to him, reverted as a young man, and eventually took his own life. The case was presented for years as proof that identity is socially constructed, and it was in fact powerful evidence for a biological reality that would not yield to upbringing.

That episode has largely dropped out of the public conversation, which I find telling. When the central experiment supporting a theory produces the opposite result, that is usually considered relevant.

Gender as biological reality in the evidence

Human beings are a sexually dimorphic species. Sex is determined at conception by chromosomes, expressed through a hormonal and developmental cascade, and written into every cell of the body. It is observable at birth in over ninety-nine per cent of cases, and it is not assigned by anyone. It is recognised.

The differences are not confined to reproduction. Skeletal structure, muscle distribution, organ size, cardiac and immune function all differ measurably, which is why forensic scientists can determine sex from a skeleton and why medicine increasingly treats sex-specific presentation of disease as clinically important. Gender as biological reality is not a religious add-on to the science. It is the working assumption of the science.

Intersex conditions are sometimes offered as a refutation, but they do not function that way. These are rare developmental variations within a two-sex framework, and they are identified as disorders of sex development precisely because there is a normal developmental pathway from which they depart. A condition described as a deviation presupposes the very reality it is said to undermine.

Where the argument actually comes from

The claim that gender is independent of the body is not a scientific discovery. It is a philosophical position, and its lineage runs through thinkers who held that the self is prior to and above any given nature, and through the postmodern conviction that categories are constructed by power rather than discovered in reality.

That is a coherent worldview, and it is worth understanding rather than mocking. But it should be recognised for what it is: a metaphysical claim about the human person, not a finding produced by evidence. When it is presented as settled science, a philosophical assertion is being smuggled in wearing a lab coat.

It also carries an implication people rarely follow through. If the body has no authority over identity, then nothing given has authority over us, and the self becomes the only remaining source of meaning. That is an enormous weight to place on an eighteen-year-old, and it is not obvious why we should think it good for them.

What culture genuinely does shape

I want to concede what should be conceded. Cultures vary considerably in what they treat as appropriately masculine or feminine. Clothing, colour, occupation and manner have shifted across centuries and continents, and much of what one generation regards as timeless turns out to be local custom.

The church has sometimes confused those customs with Scripture and then defended them as though they were biblical, which has caused real damage to people who did not fit the mould. A boy who is not sporty and a girl who is not domestic are not defective, and treating them as such has driven some of them a long way from the faith.

But conceding that expression varies is not conceding that the underlying reality varies. That there are two sexes, and that they are determined bodily rather than chosen, is not a cultural variable. The distinction between the two claims is the whole argument.

Holding this without cruelty

Everything I have said can be stated in a way that helps or in a way that wounds, and Christians have managed both. The person experiencing genuine distress about their body is not the enemy of the truth. They are usually the person for whom the culture’s answers have failed most painfully.

Gender dysphoria is a real condition and it causes real suffering. It deserves careful, compassionate attention rather than either affirmation of a false framework or a lecture on chromosomes. Those are not the only two options, though the public debate often behaves as though they were.

Paul tells us to speak the truth in love (Ephesians 4:15), and to let our speech be “gracious, seasoned with salt” (Colossians 4:6). A Christian who is right about anthropology and unkind to human beings has not obeyed either instruction.

Why this matters beyond the argument

The reason I care about this is not that I enjoy a culture war. It is that a false account of the human person leads people into decisions that cannot be undone, particularly the young. Surgical and hormonal interventions on adolescents have consequences that a fifteen-year-old cannot meaningfully consent to, and several countries have already begun to retreat from them after reviewing the evidence.

It matters theologically too. If the body carries no authority, then the doctrines of creation, incarnation and resurrection all lose their footing, since each of them assumes that bodies mean something. This is not a peripheral question about pronouns. It reaches the centre.

And it matters because people are worth telling the truth. “Then you will know the truth, and the truth will set you free” (John 8:32). I do not believe anyone is finally helped by being agreed with about something that is not so.

Answering the common objections

Two objections come up almost every time. The first is that Scripture recognises eunuchs, and that this shows a more flexible view of sex than I have described. But eunuchs in Matthew 19:12 are described in relation to marriage and childbearing, not as a third sex, and the categories Jesus lists are about circumstance, choice and calling. Nothing there overturns the verse He had quoted eight verses earlier.

The second is Galatians 3:28, “there is neither male nor female, for you are all one in Christ Jesus” (Galatians 3:28). The context is justification and standing before God, and Paul is dismantling the idea that Jew, slave or woman has lesser access to salvation. He is not abolishing sex, which is obvious from the fact that he goes on writing to husbands and wives as distinct groups.

Both objections share a method: lifting a phrase away from its subject matter and pressing it into service on a question it was not addressing. Reading Scripture in context is not a technicality here. It is the whole difference between hearing what God said and hearing what we wanted.

So, now what?

Sex is a biological reality established by God at creation, confirmed by Jesus, and consistent with what the natural sciences actually observe. The contemporary claim that it is fluid or self-determined is a philosophical position rather than a scientific finding, and Christians can say so with confidence.

Say it kindly, though. The truth is not the enemy of the person who is struggling with their body; it is the only ground on which genuine help can be built. If you know someone in that distress, the most useful thing you can offer is not an argument but a friendship that will still be there in five years. Related reading: whether the Bible supports gender identity separate from biological sex, how Christians should react to gender dysphoria and what the Bible teaches about sexuality and gender.

“Have you not read that he who created them from the beginning made them male and female?”

Matthew 19:4 (ESV)