Abstract
Sex plays a crucial role in shaping the immune response of vertebrates, leading to differing susceptibilities to diseases between females and males. This review explores the observed sexually dimorphic patterns in different pathogenic infections, immune responses, and molecular events. First, a compilation of historical guidelines for incorporating gender/sex as a variable in research studies to enhance scientific rigor, improve research outcomes, and promote better health for both sexes has been carried out. Following this, the study focuses on examining sex-based differences in immune responses across different taxa, with an in-depth review of available studies on fish, particularly regarding the prevalence of sex-related differences in parasites, viruses, and bacteria. Furthermore, the benefits of considering sexual dimorphism when evaluating the prevalence of diseases in fish management in aquaculture and ecological contexts have been discussed. Integrating sex in understanding immune responses will positively influence fish welfare, economic impacts, and policymaking, leading to more tailored and effective treatments.