Girls into Science and Technology (GIST) was an action-research project which took action to improve girls' achievement in science and technology and investigated the reasons for their underachievement. The project followed a cohort of students in eight coeducational comprehensive schools from the time they entered secondary school until they made their option choices at the end of the third year. During this time, project staff worked with teachers to devise and implement strategies to reduce sex stereotyping. Among these strategies were a program of visits by women working in technical fields, posters and worksheets about women's contributions to science, curriculum development to produce female-oriented materials, and career advice linked to option choices in schools. Results indicate that the project was successful in refining the understanding of girls' and boys' attitudes and stereotypes about science and the process of option choices. The specific focus of interventions was the stereotyping of science and technology as masculine, and in this respect the children's attitudes were considerably modified. However, children's option choices were less susceptible to GIST interventions. In addition, some teachers' attitudes altered in the desired direction. (JN)