, Pcc) is naturally gynogenic, and gynogenic Pcc producedby artificial breeding can theoretically produce solely female offspring. In laboratory culture, a higher proportionof male fish occurred in Fprogenies compared with pond culture conditions. A higher proportion of males was foundin the Fprogeny under laboratory culture (43.6%) compared with pond (4.7%) conditions. To determine the cause ofthis variant sex ratio, ovarian gene expression profiles were detected and compared between the male and female Fprogenies for different culture conditions. Results showed that expressions of most testicular sex differentiation-related,steroid receptor, and steroidogenic genes in PccFoffspring were significantly higher than those in ovaries under laboratoryculture conditions, except for Pcc-. With respect to pond culture conditions, expressionsof most testicular sex differentiation-related and steroid receptor genes in PccFoffspring were significantlyhigher than those in ovaries, except for Pcc-.Amounts of the steroidogenic genes had reversed expression patterns (male<female). The gene expression profiles forsteroidogenesis and transcriptional regulation of aromatase were different in the gonads of Fprogenies between laboratoryand pond culture conditions. The variant sex ratio may be attributed to the differential gene expression of bothsteroidogenic enzymes and transcription factors of aromatase under different culture densities, which may be associatedwith the regulation and/or synthesis of endogenous steroid hormone levels and related to different sex ratios.