Women's participation in physics remains low, with only 20% of bachelor's degrees and 19% of PhDs in physics being awarded to women. The physics classroom may serve as a barrier to women's participation when the contexts of questions and examples are stereotypically male. To study the possible effects of male contexts on student responses, two versions of a physics conceptual exam were given to students. The first version, a conceptual test in broad use in the field, included stereotypically male contexts; the second, created for the study, included stereotypically female contexts. The physics content of the questions was the same. Examination of the results show that despite identical physics, students can change their responses based on the context presented in the question. Different patterns of change were exhibited: in some instances both men and women did better on female questions, in others only one gender improved. On some questions no change was seen. The conclusion of the study is that the contexts in which physics questions are presented can have an effect on student response, and can show gender differentiation. To encourage participation of all students, instructors need to be aware of the contexts in which they present their material.