Success in STEM (Science, Technology, Engineering, and Math) is still profoundly influenced by factors other than merit such as race, gender, and socioeconomic status. Additionally to unfairness, scientific biases arise from the lack of diversity in the academic world. In this context, quantifying and providing means to alleviate these inequities is of the upmost importance. Here, we focus on question-asking behavior during scientific conferences as a global indicator of comfort in the academic world. As an interdisciplinary team, we observed the impact of gender on asking behaviour during the 2021 JOBIM virtual conference (Journées Ouvertes en Biologie et Mathématiques). We gathered quantitative and qualitative data including : detailed demographic information, question asking motivations, live observations and in-depth interviews of participants. Quantitative analysis highlighted several new findings such as an important fraction of the audience identifying as LGBTQIA+ and an increased attendance of women in virtual compared with in-person conferences. The observations revealed a persistent underrepresentation of questions asked by women. In-depth interviews of participants highlighted several barriers to oral expression encountered by women and gender minorities in STEM : negative reactions to women speech, discouragement of women and gender minorities to pursue a career in research, and gender discrimination/sexual harassment. Informed by the study, a set of guidelines for conference organizers has been written.