Sexual identity is actively maintained in specific differentiated cell types long after sex determination occurs during development. In the adult Drosophila testis, the putative transcription factor Chronologically inappropriate morphogenesis (Chinmo) is required to maintain the male identity of somatic cyst stem cells and their progeny; loss of Chinmo causes these cells to transform into female cells (Ma et al., Dev Cell, 2014). Overexpression of the male sex determinant DoublesexM (DsxM) partially rescues this sex transformation, and ectopic expression of the female sex determinant DsxF enhances it, indicating that Chinmo acts together with the canonical sex determination pathway to maintain the male identity of testis somatic cells. In the adult ovary, ectopic expression of Chinmo is sufficient to induce a male identity in adult ovarian somatic cells; here, however, it acts through a DsxM-independent mechanism (Ma et al., Development, 2016). We conclude that Chinmo is necessary and sufficient to promote a male identity in somatic cells of the adult ovary and testis and that the sexual identity of adult somatic cells can be reprogrammed in Drosophila gonads. To gain further insight into how sex identity is maintained, we are using a genome-wide approach to identify the downstream targets of chinmo in adult somatic cells. By using a technique called targeted DNA adenine methyltransferase identification (TaDa)(Southall et al., Dev Cell, 2013), we will reveal cell type-specific gene expression differences in adult wild-type and chinmo mutant tissues.