My previous post on gender self-identification and demography prompted quite a few reactions, particularly concerning my claim that sex is binary and that discussing this issue is, in itself, an act of hostility toward trans or queer people. I’d like to address these concerns directly.
“The science says sex is not binary”
Several readers objected to my statement that sex is binary, citing the widely shared Nature paper “Sex Redefined” by Claire Ainsworth (Ainsworth 2015). That article — with hundreds of citations — is often used to argue that sex exists on a spectrum, that it is bimodal rather than binary, or even that it is a social construct without material grounding.
Yet, as Ainsworth later clarified herself (Ainsworth 2017), her point was not that there are more than two sexes. Rather, she argued that biological sex cannot be reduced to a single factor like chromosomes or hormone levels, and that variation exists within each of the two sexes. This interpretation aligns with mainstream evolutionary biology (Goymann, Brumm, and Kappeler 2023; Parker, Baker, and Smith 1972; Lehtonen, Kokko, and Parker 2016).
In biology, binary does not mean “perfectly dichotomous with no variation.” It means that there are two reproductive strategies — one based on producing large immobile gametes (eggs) and one based on producing small mobile ones (sperm). Intersex conditions and atypical karyotypes represent natural variations within this framework. The existence of variation does not erase the categories themselves, just as the existence of people with chromosomal disorders does not invalidate the concept of chromosomes.
Recognizing that sex is a meaningful biological variable does not imply moral judgments about people. It simply means that sex captures aspects of human physiology that are relevant in fields like medicine, demography, and epidemiology. Denying that these differences exist would make it harder, not easier, to address issues that directly affect trans people — for example, understanding the effects of hormone therapy or ensuring equitable medical care.
A common critique is that insisting on biological sex constitutes “essentialism” and therefore implicitly denies the dignity of gender-diverse individuals. I understand why this concern arises: for many trans people, the emphasis on biology can feel like a negation of their lived experience. But that is not the point I am making.
Gender identity, as often defined in gender studies, is an internal sense of self — how someone feels or understands their gender (Butler 1990; Fausto-Sterling 2012; Westbrook and Schilt 2014). Gender expression is how that sense manifests socially. Both are distinct from sex, which refers to reproductive anatomy and physiology. These distinctions are widely recognized in feminist and queer scholarship itself.
Sometimes, our research questions concern gender identity or gendered social experience; in other cases, they concern biology. In demography or health research, we often need to know sex because reproductive patterns, disease risks, and physiological variables differ between male and female bodies. Clarifying which variable we are using — sex, gender, or both — is therefore crucial. Conceptual precision matters not for ideology’s sake, but because it determines what our data actually measure (Clayton and Collins 2014; Heidari et al. 2016; Zucker and Prendergast 2020; Preston, Heuveline, and Guillot 2001).
If we replace the sex marker in administrative data with a self-declared identity, we risk conflating two different constructs. For some individuals, the marker would indicate sex; for others, gender identity; and for yet others, both. That ambiguity undermines the consistency of official statistics. A more robust approach would be to record both variables — sex and gender identity — and use them appropriately depending on context (Office for National Statistics 2023, 2025).
“This topic is overblown — there’s no real problem”
Some have argued that the issue is exaggerated, pointing out that in countries such as Iceland, self-identification laws exist and have not led to a flood of people changing their legal sex. This is true, but the comparison requires caution. In Iceland, individuals can change their legal marker only once in their lifetime, a safeguard designed to ensure that those who genuinely need the change can do so while deterring frivolous use.
Germany’s model, by contrast, imposes virtually no restrictions on frequency. Institutional design matters. We should not dismiss early indicators, such as Dutch survey data showing substantial interest in changing to an “X” marker, precisely because other countries operate under different legal and institutional frameworks. These are, so far, the only quantitative data we have on likely behavioral responses to introducing gender self-ID in the Netherlands in particular.
Balancing personal identity and institutional functionality is possible. For instance, if we want to forecast birth rates for planning childcare facilities, we need reliable information on the population of people capable of giving birth — which depends on sex, not gender identity. Conversely, if we are studying discrimination or social exclusion, gender identity is often the more relevant variable. The sensible solution to me is to collect both, and to use them selectively depending on the research question.
As for identity documents, I would personally favor transforming the “sex marker” into a “gender marker” that individuals can change to reflect their identity, while retaining a separate sex variable within secure administrative systems for statistical and medical use. Modern data infrastructure can easily accommodate this. What matters is not introducing conceptual chaos on datasets that underpin high-stakes public policy.
“This discussion is transphobic and harmful. You are a TERF/enabling bigorty.”
I take this concern seriously. No reasonable person wants to contribute to prejudice or hostility toward any group. What I observe, however, is that two fundamentally different moral framings collide here: what might be called the harm-reduction perspective and the free-expression perspective.
The harm-reduction view starts from an empirically-grounded concern. Studies consistently show that hostile social climates correlate with poorer mental-health outcomes and higher rates of discrimination and violence against marginalized groups. Research on minority stress, for example, finds that stigma, rejection, and hostile media coverage predict depression, suicidality, and reduced well-being among LGBTQ+ people (Meyer 2003; Hatzenbuehler 2009; Bränström and Pachankis 2019). From this standpoint, public debate that questions policies like gender self-ID can feel existentially threatening. Because the same talking points are used by bad-faith actors, even good-faith discussion can be seen to legitimize those actors. The moral conclusion follows: if hateful groups say X, and you also say X, then you are either part of the problem or helping it. The goal thus becomes to reduce harm by minimizing exposure to stigmatizing discourse.
The free-expression view takes a different starting point. It holds that open discussion, not enforced silence, is what ultimately prevents prejudice, violence, and extremism. Suppressing ideas rarely makes them disappear; it tends to drive them underground, where they fester without challenge. Decades of research on psychological reactance shows that censorship and moral condemnation can strengthen commitment to contested beliefs and increase polarization (Worchel, Arnold, and Baker 1975; Rains 2013; Steindl et al. 2015). From this perspective, silencing dissent can backfire — breeding resentment that extremists are quick to exploit — thereby ironically harming the very minorities harm-reduction advocates seek to protect.
Both perspectives rest on legitimate moral intuitions and both have supporting evidence. The first emphasizes the measurable psychological and social costs of stigma; the second emphasizes the medium to long-term dangers of suppressing open discourse in a pluralistic democracy. Each carries risks if taken to extremes. The disagreement is not about whether harm exists, but about how best to minimize it: through tighter control of discourse, or through open argument governed by clear norms of civility and evidence.
For my part, I oppose hatred and discrimination against trans and queer people unequivocally. These are real and serious problems that deserve active attention. But protecting people from hatred is not the same as protecting ideas from scrutiny. Stigmatizing disagreement or branding it as (enabling) bigotry risks alienating potential allies rather than persuading them. When ordinary, good-faith people feel unable to express doubt or ask questions without social or professional punishment, resentment grows — and extremist movements are quick to exploit that resentment. History and social science both show how this dynamic fuels polarization, hatred and violence rather than inclusion, safety and equality.
A pluralistic society will never achieve total consensus on every moral or political question. Opinions cannot be eradicated by decree, nor hearts changed by shame. What we can do is build norms for disagreement that preserve mutual respect and a shared commitment to evidence and fairness. Free and open conversation—even when uncomfortable—is indispensable to that process.
Crucially, free speech and protection from harm are not opposites. They can and must coexist. Protecting trans or gender diverse people from violence and stigma does not require suppressing discussion; it requires targeting the harm itself. That means enforcing laws against hate-motivated violence and harassment; ensuring equal access to healthcare, housing, and employment; and investing in accurate public education that reduces myths and fear. It means cultivating spaces — in schools, workplaces, and media — where disagreement about policy does not spill into personal hostility and fingerpointing. None of these measures depend on restricting speech; they depend on upholding justice and civility.
The history of gay rights offers an instructive precedent. Public acceptance of same-sex relationships and marriage equality did not emerge overnight, but through decades of persuasion, reframing, and personal contact between gay and straight people. Research shows that interpersonal familiarity, visibility, and sustained engagement were among the strongest predictors of attitude change, while moral condemnation and censorship often hardened opposition (Andersen 2017; Gates 2019; Smith 2022; Library of Congress 2023; Slootmaeckers and Tronconi 2023). This indicates that durable social progress arises from dialogue and persuasion, not enforced unanimity. The same principles can guide us now. Protecting human dignity and protecting open inquiry are not competing projects; they are, in the long run, the same one.
References
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Citation
@online{fang2025,
author = {Fang, Christian},
title = {Follow-Up: {Sex,} {Gender,} {Demography,} and the {Terms} of
{Debate}},
date = {2025-10-16},
url = {https://www.christianfang.eu/posts/on_sex_again/},
langid = {en}
}