In 1997, California became the first state to conduct large-scale experimentation with single gender public education. This longitudinal study examined the impact of single gender academies in six California districts, focusing on equity implications. Data from observations and interviews with educators, policymakers, and students indicated that for most administrators, single gender schooling was a vehicle for meeting at-risk students' needs and not an end in itself. Program success was undermined by implementation challenges. Most single gender academies were, by design, not open to all students. Most parents viewed California's single gender academies as an opportunity for their children to benefit from special resources and to reduce distractions from the opposite sex. Educators ensured that equal resources were offered to both sexes but were less concerned about gender bias. Traditional gender stereotypes were often reinforced in single gender academies. Students received mixed messages about gender from their teachers. Though separating the sexes reduced classroom distractions from the opposite sex, students still experienced teasing and harassment in coeducational spaces of single gender academies. Implementation of single gender academies had positive and negative consequences for students and teachers remaining in counterpart coeducational settings. Public, single gender academies were not sustainable under California's policy framework. (Contains 34 references.) (SM)