This paper contributes to a small but significant body of research addressing issues of prejudice in science education. It is written in the form of a critical incident analysis that uses the framework of intersectionality to examine deficit ideologies and biases inherent in science as a body of knowledge as well as science teacher education. If left unchecked, these prejudices can filter through into school science education, reinforcing the stereotypes of who can contribute to the field of science. The paper makes a call for science teacher educators to support teacher candidates as they move past an academic understanding of diversity in science education to examine their personal dispositions. Suggestions are made for approaches that can be adopted to facilitate the forms of deconstruction necessary for progress to be made in this area.