A Brief Review of Sex Determination Mechanisms Across Reptile Families

Sex determination in reptiles represents one of the most diverse and evolutionarily dynamic systems among vertebrates. Across different taxa, both temperature-dependent sex determination (TSD) and genotypic sex determination (GSD) have been reported, with varying degrees of chromosomal differentiation. However, the current literature on this subject is fragmented, covering a limited number of species and genera, and often lacking cohesive overviews at the family level. This review aims to synthesize the available data concerning the sex-determination mechanisms across major reptilian families, highlighting whether species exhibit TSD or GSD, and, in the latter case, what type of chromosomal determinism (XY, ZW, multiple systems) they possess. A visual summary compiling the known genetic determinism status for a broad spectrum of reptile genera is provided, serving as a practical reference for future research. The review also discusses the knowledge gaps and the methodological challenges that continue to hinder a comprehensive understanding of sex-determination evolution in reptiles.