This paper attempts to explore one of the second-generation antipsychotics, clozapine, using it as an example to discuss the gender exclusion phenomenon in clinical studies. From examine the clinical studies of clozapine, found that the majority of clinical studies' implications and inference are only using male samples. Even some studies included a few female samples, but only using simple statistical analysis on malefemale category , did not analyze gender differences. The risk of gender exclusion in clinical studies will endanger the women, the third sex or transgender communities. Mental patients are disadvantaged group. Female mental patients are more disadvantaged in the field of male-dominated medical science, whether psychiatric or other medical studies have intentionally or unintentionally excluded women in the clinical studies. In the era of booming modern biomedical studies, psychiatric medicine must begin to seriously turn inclusion women into the clinical studies, and make efforts to analyze gender differences on the results in order to get rid of false sex equality model, to achieve the true gender equality.