Controls somatic sexual differentiation. Binds directly and specifically to the FBE (fat body enhancer) of the yolk protein 1 and 2 genes (Yp1 and Yp2). This enhancer is sufficient to direct the female-specific transcription characteristic of the Yp genes in adult fat bodies. Involved in regulation of male-specific expression of takeout in brain-associated fat body. Experimentally shown to bind zinc.