  The boundaries of feminist philosophy of biology are similarly unclear. It is not clear whether the authors cited in this entry would primarily label themselves as philosophers of biology or science studies scholars or scientists. Not surprisingly, the two general approaches to philosophy of biology are also advanced in feminist philosophy of biology. First, many feminist philosophers of biology are concerned with biological concepts and knowledge claims regarding sex and gender  (see the entry on feminist perspectives on sex and gender),  as well as the influence of gender values on biological research. Sex refers to biological differences between males and females. Gender refers to the meanings that humans make of these biological differences, and the individual and social aspects of masculinity and femininity. Since it is with our bodies that we act, and since psychological and social causes can affect our bodies, there is much debate about the relationships between sex and gender. By ‘male’ and ‘female’ I am referring to the sex of human and non-human organisms and by ‘men’ and ‘women’ I am referring to the gender of humans. Feminist analysis is often performed as a control (in a sense to be explained below) to test for the unrecognized influence of gender values on the production of knowledge, in existing knowledge claims, and in the choices of research projects. These gender values can include sexism (devaluation, in practice primarily of women, based on traditional stereotypes of gender roles) and androcentrism (a focus on men or males and the neglect or exclusion of women or females). As I will explain in more detail below, feminist investigations of the relationships between gender values, and the practices and products of the biological sciences, can take place in a range of epistemological projects. Some projects focus on removing gender bias, and others focus on developing an understanding of the role of social values, including gender values, in biological research.