Understanding gender related disparities in science is an essential step in tackling these issues. Through the years, bibliometric studies have designed several methodologies to analyze scholarly output and demonstrate that there are significant gaps between men and women in the scientific arena. However, gender identification in itself is an enormous challenge, since bibliographic data does not reveal it. These bibliometric studies not only focused on publication output and impact, but also on cross-referencing output, promotions and tenure data, and other related curriculum vitae (CV) information. This chapter discusses the challenges of tracking gender disparities in science through bibliometrics and reviews the various approaches taken by bibliometricians to identify gender and analyze the bibliographic data in order to point to gender disparities in science.