This article has stressed on actual problem to take into consideration the gender's ratio in clinical trials for following the ethical principles and maintain data quality. It is shown that the essential different in medications activity are depended from gender factors. Bioethical and gender indexes have been companied at the different phases of planning the study, selecting the participants and conducting clinical trials. In article is presented that the data of gender's ratio in R&D of medications dose should be available and the evaluation of pharmacological features of drug necessary to make in clinical trials where gender balance of participants take place. All potential problems of gender balance connected with cultural, religion and social - economic factors. There are the specific of gender's behavior for different groups of participants what influence on following ethical standards in the process of obtaining and documenting informed consent. Subject protection and the collecting of relative data requires the transparency of gender's ratio concerning with trial's participants.