The Elimination of Biological Sex?

A Critical Analysis of Diethard Tautz’s Theses (2023/2024) – Abstract¹

In his publications ‘Biological Sex – The Illusion of Binarity’ (2023) and ‘Female – Male – Diverse: Is it that simple?’ (2024), evolutionary geneticist Diethard Tautz posits that biological sex development should be regarded as an uncategorised holistic process. He advocates the dissolution of binary categories in favour of a “continuous spectrum”. The present analysis examines whether Tautz succeeds in establishing a viable new concept of sex and to what extent his argumentation stands up to scientific and logical standards.

The text subjects Tautz’s argumentation to an interdisciplinary examination:

• Evolutionary biology: Comparison with the concepts of anisogamy, reproductive strategies and fitness.
• Logic and philosophy of science: Identification of categorisation errors, is-ought fallacies (Hume) and performative contradictions.
• Perceptual psychology: Analysis of the human brain’s classification processes.

The key findings are as follows:

• Performative contradiction: Tautz calls for the abandonment of binary categories, yet consistently uses them in order to formulate his evolutionary biological explanations (e.g. the costs of two sexes, 50-per-cent distribution in populations) in the first place. Without the premise of ‘male’ and ‘female’ based on anisogamy, his arguments regarding sexual selection and recombination lose their biological foundation.
• Confusion of ontology and normativity: Tautz repeatedly commits the idealistic fallacy by inferring the non-existence of biological facts (binary reproduction) from an ethical norm (individual freedom, rejection of role constraints). The existence of biological dimorphism is falsely presented as a compelling cause of social repression.
• Category error: sex vs. gender: Tautz attempts to integrate the psychological-sociological concept of ‘gender fluidity’ into general evolutionary biology. The analysis shows that this transfer fails: Gender identity is a human mental construct. Applying it to other species is empirically untenable and results in anthropocentrism. Genetic variability (phenotype) is impermissibly equated with identity fluidity. Evolution selects for reproductive success, not for subjective experience.
• Perception and brain research: Tautz describes the binary classification of humans as “schizophrenic”. The analysis counters this by arguing that the ability to categorise (class) whilst simultaneously perceiving individuality (object) is a vital cognitive function. Furthermore, recent studies (e.g. Ryali et al.) contradict Tautz’s claim that there are no systematic differences in the brains of men and women.

This suggests that Diethard Tautz has not succeeded in eliminating biological sex as a category. His attempt to reinterpret biology through the lens of identity politics results in the loss of scientific precision.

• Scientific utility: A concept of sex based solely on identity is of no use to empirical biology and sex-specific medicine.
• Influence of the zeitgeist: Just as Tautz accuses Darwin of a zeitgeist bias, he himself appears to succumb to the current trend of social constructivism, which relativises the reality of reproductive biology in favour of political inclusion goals.

The analysis concludes by stating that the recognition of biological binary does not imply a devaluation of individual diversity, but its denial undermines the foundations of evolutionary biology.