Tilapias are the second largest group of fish produced worldwide, due to their great plasticity and ideal aquaculture traits, particularly the Nile tilapia. On most tilapia farms, sex control is necessary to increase profitability, due to early and continuous reproduction and female mouth-brooding, and to benefit from the males' faster growth rate. This review presents the different ways to produce all-male populations by genetic approaches, such as the use of YY males (or ZZ females in the blue tilapia), and hormonal or high temperature sex reversal treatments, presenting the advantages and drawbacks of each method, as well as protocols for their use. Androgen treatment is still the predominant means to generate monosex male offspring, due to its simplicity, efficiency and price. The hormone amounts currently used worldwide, and its consequences on biodiversity, are discussed, regarding the sustainability of tilapia farming and taking into account growing consumer awareness. Results regarding 17a-methyltestosterone (MT) accumulation and the possible use of MT-degrading bacteria are discussed. More sustainable alternative methodologies can be potentiated. Current research status on the sex-determining loci in Nile, blue, Mozambique and black chin tilapias is presented. Finally, we show the available genetic and phenotypic sex markers that can accelerate progeny testing, rapidly identifying particular genotypes and phenotypes of interest such as YY males or ZZ females, as well as being important for selection programs.