Sex in Limbo: Noninvasive Prenatal Testing and the (Un)Making of Sex Chromosome Variations.

In 2017, Belgium became the first European country to offer full access to noninvasive prenatal testing (NIPT) for all pregnant individuals. NIPT is commonly used to screen for aneuploidies like Down syndrome and assess fetal sex. One consequence of genome-wide NIPT is the potential to detect sex chromosome variations (SCVs), whose inclusion in the NIPT panel remains debated. This paper examines the moral ambivalence surrounding the prenatal detection of SCVs in light of the ongoing medicalization of intersex bodies. Combining humanities and ethnography, I explore how two techniques have made SCVs visible to the scientific community. I contrast NIPT with the Barr body, a sex testing method developed in the 1950s. I ask, what are the social and material consequences of each mode of making sex visible? In turn, how does it inform the debate on including SCVs in prenatal screening? First, I show how SCVs have been historically framed as medical conditions, disconnected from intersex concerns. Drawing on fieldwork on NIPT in Belgium, I highlight how the framing of SCVs as pathological categories is underpinned by epistemic uncertainties related to the role of vision in scientific practice. I argue that contemporary genetics' approach to SCVs reflects a continuation of the gender binary framework, wherein SCVs are treated as medical conditions rather than as evidence that sex, like gender, is socially mediated. Ultimately, I suggest that integrating an intersex perspective into the conversation about SCVs could offer an alternative to the medicalization of sex differences.