This paper considers whether apparently non-essentialist accounts of biological sex can avoid sex-essentialist uptake when expressed via generics. Recent work in philosophy of biology has defended realist accounts grounded in anisogamy as both empirically robust and compatible with diversity. I argue that Paul E. Griffiths' sex concept is the most compelling of these views and is not vulnerable to sex essentialism in itself. However, the generics literature shows that generic statements expressing biological generalisations can nonetheless have sex-essentialist uptakes. Drawing on Sterken's account of quantificational force and Leslie's cognitive mechanisms—characteristic dimensions and counterexample resistance—I argue that even Griffiths' carefully non-essentialist account gets processed as an absolute generic, erasing the nuance that distinguishes it from traditional gametic essentialism. Once essentialised at the level of cognition, these generics feed into broader social consequences: the assumption that biological sex determines behavioural dispositions, emotional capacities, and social roles. Generic expressions about behavioural dispositions, emotional capacities, and social roles inherit their apparent biological authority from realist sex concepts, lending scientific legitimacy to stereotypes that Griffiths' metaphysics was never designed to support. Ultimately, I argue that sex-essentialist uptake places significant constraints on the ability of realist accounts of sex to remain non-essentialist in practice.
