A panoramic view of the expression and function of the Doublesex/DMRT gene family in <i>C. elegans</i>

, we find that 6 DMRTs display sexually dimorphic expression in somatic and/or reproductive tissues, including in cell and tissue types not previously known to be sexually dimorphic. In the nervous system, DMRT protein expression covers many, although not all, known sexually dimorphic neuron types. Analyses of DMRT null mutant alleles reveal a suite of neuronal differentiation defects, ranging from altered neurotransmitter identities and switched neuropeptide signatures to impaired glia-to-neuron transdifferentiation. Several DMRT proteins do not exhibit sexually dimorphic expression, indicating roles beyond sexual differentiation. Similar comprehensive analyses of DMRT genes in other organisms may help to better understand the extent and regulation of sex-specific cellular differentiation programs.