Like many species, Drosophila are sexually dimorphic –females are larger than males. Jamila Horabin now proposes that Sex-lethal (Sxl), the Drosophila sex-determination switch, may control this size difference through its effects on the Hedgehog(Hh) signalling pathway (see p. 4801). Sxl, which controls female sexual development, is also part of the Hh cytoplasmic signalling complex. Horabin shows that Sxl enhances the levels and rates of nuclear entry of the Hh signalling target Cubitus interruptus and the expression of Hh downstream targets, including decapentaplegic, the Drosophila TGFβ homolog. Furthermore, male and female discs expressing ectopic Sxl overgrow. Horabin suggests, therefore, that the augmentation of Hh signalling by Sxl could provide a mechanism by which overall body size is increased without changing the body plan in Drosophila and possibly in other sexual dimorphic organisms that use Hh for patterning.