Groups and educators have sought to construct gender-sensitive learning environments for women and girls in science, thus providing them with opportunities to legitimately participate in the science and science education communities. Results of the study reported in this paper show that women science educators who work to provide such contexts experience multiple obstacles, conflicts, tensions, and dilemmas that are situated in issues of power and politics which interrupt their efforts to facilitate girls' and women's opportunities to engage in science. Groups studied included an after-school science club for girls under the direction of a woman science educator, and a group of university women working in science at an academic research institution. Data were collected in the form of interviews, field notes taken during participant observation, and analysis of group materials and other documents. Suggestions for solving some of the dilemmas are provided that include providing women and girls with contexts to meet together, speak, and make decisions within multiple contexts such as local science programs, the everyday school and work environment, and national decision-making structures. Contains 28 references. (PVD)