We did not find sex-biased polyclonality in TERT promoter-mutated tumours, but did detect a putative bias in the proportion of polyclonal CTNNB1-mutated tumours (80% of male-derived tumours are polyclonal vs. 46% of female-derived tumours, 95% CI = −0.019–0.70, prop-test p = 0.039). The gene discussed is CTNNB1; the disease is neoplasm.