The sole functional allele of the Gata4 gene is sufficient to support adrenocortical development and steroidogenesis. Adrenal sections from control (A and B) and ROSAmT/mG; Sf1Cre;Gata4flox/+Gata6flox/flox (C–J) fetuses at E15.5 were stained for 3βHSD (red) (A–F) and TH (bright green) (A–H); SF1 (bright green) (I and J) and 3βHSD (red) (I and J). In the ROSAmT/mG; Sf1Cre;Gata4flox/+Gata6flox/flox adrenals, EGFP expression traces SF1Cre-mediated gene excision only by displaying membrane staining (EGFPm, dark green) (C–J). DAPI was used as nuclear staining (blue). Scale bars, 200 μm (C, E, G, and I), 100 μm (A, D, F, and H), 50 μm (D, F, and H), and 20 μm (B and J).