# Who Is A Woman? Biology Says: It's Complicated.

*A short refutation of the "but biology" argument*

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The favourite weapon of transphobes is biology. "Male and female are immutable," they say. "You can't change your sex." It sounds scientific. It isn't.

**Biology doesn't do neat categories.**

Sex in humans is not a binary. It's bimodal — meaning there are two broad clusters of characteristics (hormones, chromosomes, gonads, genitalia) that tend to appear together, but overlap significantly. There is no single "sex chromosome" test that sorts every human cleanly into one column or the other. XX and XY are the most common patterns. They are not the only ones.

Around 1.7% of the global population — roughly 136 million people — are born with intersex conditions. Some are visible at birth. Others only emerge at puberty, or never show up without genetic testing. Nature does not recognise the two-column table we were taught at school.

**So what exactly is the "biological fact" being invoked?**

When someone says "trans women are male," they mean: we have male-typical chromosomes, or male-typical anatomy at birth. That is often true. It is also true that many cisgender women have male-typical features, male-typical chromosomes, or male-typical medical conditions. The assumption that "biology" produces two clear, clean, mutually exclusive categories is simply wrong.

The honest scientific position is: sex characteristics exist on a spectrum. Gender identity exists independently of that spectrum. These are separate phenomena.

**The brain research is inconvenient for biological fundamentalists.**

Brain imaging studies have repeatedly found that trans people's neural architecture often resembles that of their experienced gender rather than their assigned sex — particularly in regions associated with body perception and self-recognition. The APA, the WHO, and every major medical body agree: gender dysphoria is not a delusion. It is a genuine mismatch between body and self, with measurable correlates in brain structure.

Biological fundamentalists are not arguing from science. They are selecting from science — taking the parts that support their position and ignoring the rest.

**The question "what is a woman?" has no clean biological answer.**

Can you define "woman" using only biology — without reference to social role, appearance, or self-identification — in a way that includes all cisgender women and excludes all trans women? No one has ever managed it. Every attempted definition either excludes some cisgender women (women with Androgen Insensitivity Syndrome, women who have had hysterectomies, postmenopausal women) or includes some trans women.

Gender is performative, as Judith Butler observed. We recognise each other as men or women through social presentation, convention, and ritual — not through chromosome counts. Your GP knows your biology. Your colleagues do not. The social category "woman" is a cultural construction that exists independently of any single biological marker.

**The real argument is political, not scientific.**

What biological fundamentalists actually want is a legal definition of "woman" based on a narrow set of genital and chromosomal criteria — one that excludes trans women from protections, services, and spaces. This is not a scientific debate. It is a political project dressed in the language of common sense. The science does not support it.

A woman is a person who lives as a woman. That is the only definition that holds. Everything else is detail.

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*Bea Groves-McDaniel is a 70-year-old trans woman and semiretired educator*