When the public school system of Ontario, Canada, began offering an all-female computer science course for girls in grade 11, female enrollment in computer science increased to approximately 40%. This increased enrollment level has been maintained for 3 years. The new course's effects on girls' attitudes were examined in a survey of 184 grade 11 students enrolled in the Ontario computer science course. The sample included 45 girls enrolled in all-female sections of the course and 114 boys and 25 girls enrolled in mixed-gender sections of the course. Girls from the all-female classes and boys reported similar levels of perceived teacher support and similar levels of confidence and intrinsic value, whereas girls from the mixed-gender classes reported less perceived support, lacked the confidence of their peers, and did not enjoy working with computers as much as boys or the girls from the all-female sections of the course did. A successful summer camp program to increase elementary students' understanding of and skills in science and engineering was described along with efforts to promote high technology for girls. The strategy included building a consensus with a local high-technology firm to develop a proactive enrollment strategy and positive learning environment and talking with female students to diminish sex stereotypes. (Contains 5 figures and 8 references.) (MN)