In this chapter, we investigate how gender has been established and conceptualized in feminist thought and what value the concept has for debates in bioethics. We summarize major approaches to gender, explore the sex-gender distinction, and address approaches and empirical evidence for understanding sex and gender as a spectrum and continuum. We then investigate the relevance and importance of the gender lens in bioethics. We argue that so far, gender power imbalances have been insufficiently addressed in bioethics and when they have been, this has been done in a Western-centric manner, including in feminist bioethics. Thus, we contend that anticolonial approaches to gender are warranted to advance and democratize debates within feminist bioethics and bioethics more broadly.