Disagreement over the biological concept of sex within the German sceptical movement

Extended abstract - switch to the German version to read the full analysis with many references.

Background and Objectives

We analyse the ideological split within the German sceptical movement, which led in 2024 to the breakaway of the group Skeptix from the established GWUP. As no official policy paper has been issued by Skeptix, the text examines this group’s new self-conception through the lens of the debate on biological sex. To this end, a text by Skeptix member and physicist Holm Hümmler is compared with a foundational article by biology educator Dittmar Graf (GWUP). The historical context of this debate is the conflict, ongoing since the 1970s, between evolutionary biology and sociological currents (such as radical social constructivism and gender studies following Judith Butler).

Subject of the study: Two opposing positions

1. The position of Holm Hümmler (Skeptix)

In his text, Hümmler applies a pattern of argumentation from the critique of esotericism (which he terms ‘quantum quark’) to the biological concept of sex. He accuses advocates of biological binary sex of arguing in three steps:

1. Beginning with a true, banal premise (there are two types of reproductive cells).
2. They then move on to a vague definition in order to construct exactly two sexes.
3. From this, they derive a social norm that is exclusionary and transphobic.

Hümmler posits that the biological concept of sex is vague, context-dependent and is being misused to support misanthropic ideologies. He also draws on an article by the biologist Diethard Tautz, who attempts to soften categorical concepts of sex in favour of social-constructivist concepts.

2. The position of Dittmar Graf (GWUP)

In contrast to this is the biologically descriptive position of Dittmar Graf. Graf defines biological sex in functional-biological terms via anisogamy (the production of large and small germ cells / macro- and microgametes). This dichotomy of the sexes is not a social construct, but a fundamental, evolutionary fact.

Graf emphasises the strict separation of sex(biological sex) and gender (social gender role). Variations in sexual development (intersexuality) do not refute the fundamental binary nature of reproduction. Furthermore, Graf warns against the moralistic fallacy, whereby conclusions about biological facts (how something is) are drawn from moral postulates (how something ought to be).

Critical analysis of the arguments

Hümmler’s text is subjected to an analytical critique, which identifies serious argumentative, linguistic and methodological shortcomings:

• Straw man argument and fallacies: The three-step argumentation implied by Hümmler does not exist in biology. Evolutionary biology does not derive social norms from the mere fact of anisogamy (avoiding the naturalistic fallacy). Conversely, Hümmler succumbs to the moralistic fallacy when he rejects biological facts on moral grounds.
• Linguistic inconsistency: Citing the biologist and philosopher Tomás Bogardus, the text refutes Hümmler’s claim that the terms ‘male’ and ‘female’ are ambiguous, indeterminate or purely context-dependent in biology. Across species, these terms have a clear core meaning (anisogamy).
• Rhetoric and guilt by association: Hümmler shies away from a factual debate and instead employs moralising, combative terms (e.g. misanthropic, bullshit, rambling) as well as the rhetorical ploy of guilt by association (references to the AfD) to delegitimise the biological definition.

Conclusion and comparison

Hümmler’s argument is untenable in the field of biology. Abandoning the biological concept of sex renders not only evolutionary biology, but also medicine and even the social sciences (including research into gender dysphoria) incomprehensible. Whilst biological facts should not be misused to set standards, ignoring them when weighing up social interests (e.g. in women’s sport or in medicine) is anti-scientific.

An examination of the two documents reveals an irreconcilable methodological rift within the sceptical movement:

• Graf (GWUP) advocates realism, universalism and objectivity. He draws a clear distinction between evolutionary facts and social values.
• Hümmler (Skeptix) advocates moralism, alignment with identity politics and linguistic vagueness. He employs straw man arguments and moral judgements in place of objective criticism.

Science and a rationally operating sceptical movement must adhere to universal, descriptive standards. Abandoning the pursuit of objective truth in favour of subjective group truths (neo-left identity politics) reduces science to a mere tool of political ideologies.