The article reviews the sex bias in neuroscience and biomedical research, highlighting the underrepresentation of female subjects in both human and animal studies. Despite mandates for gender inclusion in human clinical trials since 1993, similar initiatives for female animals are lacking. The authors found that male bias was evident in 8 out of 10 biological fields, with neuroscience showing the most pronounced male bias (5.5:1 ratio of male to female studies). This bias has increased over the past half-century in non-human studies but has declined in human studies. Studies often fail to analyze results by sex, and the underrepresentation of females in animal models of disease compromises our understanding of female biology. The majority of articles in several journals focus on rats and mice, neglecting other useful animal models. The belief that non-human female mammals are intrinsically more variable and problematic for research is unfounded. The authors recommend that when only one sex is studied, this should be clearly indicated in article titles, and funding agencies should favor proposals that investigate both sexes and analyze data by sex. They also suggest that journal editors adopt mandatory policies for non-human animal research to ensure the inclusion of females.The article reviews the sex bias in neuroscience and biomedical research, highlighting the underrepresentation of female subjects in both human and animal studies. Despite mandates for gender inclusion in human clinical trials since 1993, similar initiatives for female animals are lacking. The authors found that male bias was evident in 8 out of 10 biological fields, with neuroscience showing the most pronounced male bias (5.5:1 ratio of male to female studies). This bias has increased over the past half-century in non-human studies but has declined in human studies. Studies often fail to analyze results by sex, and the underrepresentation of females in animal models of disease compromises our understanding of female biology. The majority of articles in several journals focus on rats and mice, neglecting other useful animal models. The belief that non-human female mammals are intrinsically more variable and problematic for research is unfounded. The authors recommend that when only one sex is studied, this should be clearly indicated in article titles, and funding agencies should favor proposals that investigate both sexes and analyze data by sex. They also suggest that journal editors adopt mandatory policies for non-human animal research to ensure the inclusion of females.