Cell division cycle 42 (CDC42) is a member of the Rho-GTPase family. It is 191 amino acids in length, located on chromosome 1p36.12, and it contains a molecular weight of 21.33 kDa. 1 CDC42 was first identified in budding yeast in 1997, and it plays an integral role in the regulation of cell motility, cell proliferation, cytoskeleton and in particular, microfilament-dependent cell polarity. 2-5 CDC42 is highly homologous and conserved in human and yeast, and can be hypothesized to play a fundamental role in cell biology. 6 CDC42 also plays a central role in the establishment of cell polarity. 7 The first evidence of the involvement of CDC42 in the establishment of cell polarity came from a study by Adams et al. in yeast, 8 which showed that a novel effector domain of CDC42 is involved in triggering the yeast G2/M transition and can couple the cell cycle to play a role in cytoskeletal rearrangements. 9 Later, in Drosophila oocytes, it was found that Drosophila maternal effector proteins interact with both actin through the WH2 structure and CDC42, thereby localizing GTPase to the actin cytoskeleton. 10 It is noteworthy that the multifactor-controlled 'inactivation-activation' process of CDC42 also makes it play an important role in the combined regulation of multiple genes and signalling pathway network, and the synergistic effect of multiple genes makes the process of female gametogenesis more precise. Thus, the role of CDC42 in female vertebrate gametogenesis has been gradually unveiled. In this context, the aim of this paper is to review the role played by CDC42 in controlling female gametogenesis and to summarize the related mechanisms. We will describe how CDC42 regulates female gametogenesis (including four chapters on follicular reserve and primordial follicle activation, meiosis, fertilization and embryo formation); similarly, we will briefly